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1

Nerve and Nerve Root Biomechanics  

Microsoft Academic Search

\\u000a Together, the relationship between the mechanical response of neural tissues and the related mechanisms of injury provide\\u000a a foundation for defining relevant thresholds for injury. The nerves and nerve roots are biologic structures with specific\\u000a and important functions, and whose response to mechanical loading can have immediate, long-lasting and widespread consequences.\\u000a In particular, when nerves or nerve roots are mechanically

Kristen J. Nicholson; Beth A. Winkelstein

2

Lumbosacral intrathecal nerve roots: an anatomical study  

Microsoft Academic Search

Background  The lumbosacral intrathecal anatomy is complex because of the density of nerve roots in the cauda equina. Space-occupying\\u000a lesions, including disc herniation, trauma and tumor, within the spinal canal may compromise the nerve roots, causing severe\\u000a clinical syndromes. The goal of this study is to provide spinal surgeons with a detailed anatomical description of the intrathecal\\u000a nerve roots and to

Mehmet Arslan; Ayhan Cömert; Halil ?brahim Açar; Mevci Özdemir; Alaittin Elhan; ?brahim Tekdemir; Shane R. Tubbs; Ayhan Attar; Hasan Ça?lar U?ur

2011-01-01

3

Redundant nerve roots of the cauda equina.  

PubMed

The authors have critically reviewed 8 cases which have come under their observation of a lumbosciatic syndrome due to redundant nerve roots of the cauda equina. Some of the clinical and myeloradiculographic features appear to be characteristic of this rare syndrome. Surgical intervention by decompressing the nerve roots of the cauda equina offers a very favourable prognosis. PMID:6234260

Pau, A; Sehrbundt Viale, E; Turtas, S; Zirattu, G

1984-03-01

4

Sheaths of the spinal nerve roots  

Microsoft Academic Search

The present study was carried out to investigate the permeability of normal spinal nerve root sheaths around dorsal and ventral roots in the rat. In vivo studies were performed using Evans bluealbumin and lanthanum chloride as tracers. The Evans blue-albumin complex is macromolecular in size and lanthanum ions are small and easily visible in the electron microscope. Both tracers were

C. Å. V. Pettersson

1993-01-01

5

Redundant nerve roots of the cauda equina.  

PubMed

Four cases of redundant nerve roots of the cauda equina are reported, and the pertinent literature is reviewed. This disorder mainly affects males. The clinical history ranges from months to decades. The illness often starts with low back pain or sciatica, or both. Motor and sensory impairment of the legs dominate the further course of the disease. Serpentine filling defects in the column of contrast are a characteristic (but inconstant) feature on myelograms. Abatement of signs and symptoms occurs following adequate decompression of the redundant roots. PMID:6272439

Pau, A; Viale, E S; Turtas, S; Viale, G L

1981-10-01

6

Reconstruction of nerve root sheaths for sacral extradural spinal meningeal cysts with spinal nerve root fibers.  

PubMed

This study analyzed the clinical characteristics and outcomes of sacral extradural spinal meningeal cysts with spinal nerve root fibers treated by reconstruction of the nerve root sheaths. The relationships between the cysts and spinal nerve root fibers were examined microscopically, the cysts were partially excised, and the defects were oversewn to reconstruct the nerve root sheaths. The Improved Japanese Orthopedic Association (IJOA) scoring system was used to evaluate preoperative and postoperative neurological function. Thirty-eight patients were included in this study, with a mean age of 41.4 ± 15.57 years. The mean IJOA score was 18.8 ± 1.32 preoperatively and 19.6 ± 0.65 postoperatively, which was a significant difference (t=-3.77, P=0.001). These results indicate a significant improvement in neurological function after surgery. The most significant improvement in neurological function was sensation (z=-2.86, P=0.004), followed by bowel/bladder function (z=-2.31, P=0.02). PMID:24008383

Sun, Jianjun; Wang, Zhenyu; Li, Zhendong; Wu, Haibo; Yen, Ruyu; Zheng, Mei; Chang, Qing; Liu, Isabelle Yisha

2013-11-01

7

Visualization of sacral nerve roots via percutaneous intraspinal navigation (PIN).  

PubMed

A percutaneous technique for visualizing sacral nerve roots is described. A fiberscope was inserted into the subarachnoid space through a sheath that was inserted via a percutaneous lumbar puncture. The sacral nerve roots were identified with endoscopic visualization and x-ray fluoroscopy localization of the endoscope. These images were compared with those obtained from a videoscope, which revealed better imaging. Specific sacral nerve roots can be identified by using a combination of endoscopy and x-ray fluoroscopy. This technique may enable minimally invasive interventions such as lysis of adhesions, arachnoid cyst decompression, selective dorsal rhizotomy, and more selective and precise nerve stimulation electrode placement. PMID:16219858

Fujimoto, Takuya; Giles, Brian P; Replogle, Robert E; Fujimoto, Hitomi; Miller, Susan L; Purdy, Phillip D

2005-10-01

8

Spinal root origins and innervations of the suprascapular nerve.  

PubMed

The suprascapular nerve branches provide efferent innervation to the supraspinatus and infraspinatus muscles as well as sensory innervation to the shoulder joint. This study was carried out to verify the spinal root origins and innervations of the suprascapular nerve. Fifty samples of the suprascapular nerve taken from 37 adult Korean cadavers were used in this study. The suprascapular nerve was found to comprise the ventral rami of the C5 and C6 in 76.0% of the fifty samples; C4, C5, and C6 nerves in 18.0%; and C5 nerve in only 6.0%. The C5 nerve was consistently shown to be the largest in mean diameter and was found to be a major contributor of nerve fibers leading to the suprascapular nerve. This study shows that the main spinal component of the suprascapular nerve is C5 nerve. In most cases, the rate of the involvement of the C4 and C6 nerves (18.0 and 94.0%, respectively) with the suprascapular nerve was less than that of C5 nerve. C4 and C5 nerves were shown to contribute nerve fibers to the supraspinatus and infraspinatus muscles and to both shoulder joints, whereas C6 nerve displayed variable patterns of innervation. PMID:19937327

Shin, Chuog; Lee, Seo-Eun; Yu, Kee-Hyun; Chae, Han-Kyo; Lee, Kyu-Seok

2010-03-01

9

Formation of median nerve by three roots: A case report  

Microsoft Academic Search

During routine dissection of an adult male cadaver in the Department of Anatomy, College of Medical Sciences, Bharatpur, Nepal, the right median nerve was found to be formed by three roots. The finding was noted after thorough and meticulous dissection of the upper limbs of both sides (axilla, arm, forearm and palm). Out of the three roots forming the anomalous

N. Satyanarayana; C. K. Reddy; P. Sunitha; N. Jayasri; V. Nitin; G. Praveen; R. Guha; A. K. Datta; M. M. Shaik

2010-01-01

10

Median nerve deformation and displacement in the carpal tunnel during finger motion.  

PubMed

The objective of this study was to evaluate the correlations between deformation and displacement of median nerve and flexor tendons during finger motion in the carpal tunnel for both carpal tunnel syndrome (CTS) patients and healthy controls. Sixty-two wrists of 31 asymptomatic volunteers and fifty-one wrists of 28 idiopathic CTS patients were evaluated by ultrasound. The displacement of the median nerve and the middle finger flexor digitorum superficialis (FDS) tendon, as well as area, perimeter, aspect ratio of a minimum enclosing rectangle, and circularity of the median nerve were measured in finger extension and flexion positions. Deformation indices were defined as the ratios of indices in finger extension and flexion positions. The correlations between displacement and deformation indices were evaluated. There were significant correlations between nerve palmar-dorsal displacement and deformation indices (p < 0.05). The aspect ratio deformation index showed the strongest correlation to palmar-dorsal displacement of the nerve (-0.572, p < 0.01). This study showed that there is a relationship between median nerve deformation indices and nerve palmar-dorsal displacement in the carpal tunnel. Since the highest correlations were between palmar-dorsal nerve displacement direction and aspect ratio deformation index, these parameters may be helpful to understand the pathophysiology of CTS. PMID:24038546

Yoshii, Yuichi; Ishii, Tomoo; Tung, Wen-Lin; Sakai, Shinsuke; Amadio, Peter C

2013-12-01

11

Anatomical feasibility of transferring the obturator and genitofemoral nerves to repair lumbosacral plexus nerve root avulsion injuries.  

PubMed

Nerve transfer is a valid surgical procedure for restoring lower-extremity function after lumbosacral plexus nerve root avulsion. We determined the anatomical feasibility of transferring the obturator and genitofemoral nerves for this purpose. The obturator, genitofemoral and femoral nerves, and the S1 and S2 nerve roots on both sides were exposed in 10 cadaver specimens. We traced all nerves to their origins. The lengths of the obturator and genitofemoral nerves were measured from their origins to their exits from the abdominal cavity. The transverse and longitudinal diameters of all nerves were measured. Specimens were obtained to determine the total number of myelinated fibers in each nerve. The proximal part of the left obturator nerve was anastomosed with the distal part of the right femoral nerve, between the vertebrae and the peritoneum, with an overlap of 2-3 cm. Similarly, the proximal parts of the right obturator and genitofemoral nerves were anastomosed with the ipsilateral S1 and S2 nerve roots, respectively, with an overlap of 2-4 cm. The obturator nerve contained approximately one-third of the number of fibers (4,300-7,800) presenting in the femoral nerve (13,500-21,000). Similarly, the number of fibers found in the S1 nerve root was in the range 5,200-8,900. The genitofemoral nerve contained approximately half the number of fibers (3,000-4,500) presenting in the S2 nerve root (4,600-8,400). The obturator and genitofemoral nerves could be suitable donor nerves for repairing lumbosacral plexus nerve root avulsion. Clin. Anat. 27:783-788, 2014. © 2013 Wiley Periodicals, Inc. PMID:24288352

Gang, Yin; Wang, Tienan; Sheng, Jun; Hou, Chunlin; Lin, Haodong

2014-07-01

12

[Nerve root compression by gas containing lumbar disc herniation--case report].  

PubMed

The radiographic appearance of gas collection in the intervertebral disc represents the so-called "vacuum phenomenon." Incidence of the vacuum phenomenon on plain radiographs is reported to be 1-20%, whereas gas-containing disc herniations are rarely observed. We present a case report involving a patient with L4/5 gas-containing disc herniation, which was demonstrated by CT and MRI scans and was also surgically documented. A 48-year-old man with no previous back trauma presented with a 14-day history of left leg pain. On neurologic examination, the straight leg raising test was positive at 60degrees. Leg muscle strength was weak on the extensor hallucis longus. Sensory disturbances and abnormalities in deep-tendon reflexes were not observed. Lumbar roentogenograms showed "vacuum phenomenon" at L2/3, L4/5 and the L5/S disc space. MRI indicated a herniated disc at L4/5 displacing the dural sac and a focal low intensity in the lesion. Administration of an epidural block relieved the patient's symptoms. Ten months later, the patient reported a gradual return of similar left leg pain. His symptoms did not respond to conservative management. Lumbar spine films indicated abnormalities identical to the original results. MRI showed an enlarged area of low intensity with compression of the left L5 nerve root. In addition to recurrent pain, discography with metrizamide injections confirmed the presence of intradiscal gas and compression of the left L5 nerve root. During surgery, a gray-bluish air mass compressing the L5 nerve root was identified. Manipulation of the mass resulted in rupture and the release of gas. The displaced nerve root immediately relaxed to its normal position. Seven months after the operation, the patient remains free of pain. PMID:19526837

Yasuoka, Hiroki; Nemoto, Osamu; Kawaguchi, Masahisa; Naitou, Satoko; Yamamoto, Kouji; Ukegawa, You

2009-06-01

13

Redundant nerve roots of the cauda equina. A case report.  

PubMed

One further case of redundant nerve roots of the cauda equina is described, and a review of eleven comparable cases in the literature is provided. In the authors' opinion, this disease appears to be a congenital anomaly, frequently but not necessarily associated with spinal changes. PMID:941719

Pau, A; Turtas, S

1976-01-01

14

Extradural Corticosteroid Injection in Management of Lumbar Nerve Root Compression  

Microsoft Academic Search

The effect of extradural corticosteroid injection in patients with nerve root compression syndromes associated with degenerative disease of the lumbar intervertebral discs was assessed in a double-blind controlled trial on 100 consecutive inpatients assigned by random allocation to treatment and control groups. Assessment during admission and at three months revealed statistically highly significant differences in respect of relief of pain

T. F. W. Dilke; H. C. Burry; R. Grahame

1973-01-01

15

The Use of the Phrenic Nerve Communicating Branch to the Fifth Cervical Root for Nerve Transfer to the Suprascapular Nerve in Infants with Obstetric Brachial Plexus Palsy  

PubMed Central

Traditionally, suprascapular nerve reconstruction in obstetric brachial plexus palsy is done using either the proximal C5 root stump or the spinal accessory nerve. This paper introduces another potential donor nerve for neurotizing the suprascapular nerve: the phrenic nerve communicating branch to the C5 root. The prevalence of this communicating branch ranges from 23% to 62% in various anatomical dissections. Over the last two decades, the phrenic communicating branch was used to reconstruct the suprascapular nerve in 15 infants. Another 15 infants in whom the accessory nerve was used to reconstruct the suprascapular nerve were selected to match the former 15 cases with regard to age at the time of surgery, type of palsy, and number of avulsed roots. The results showed that there is no significant difference between the two groups with regard to recovery of external rotation of the shoulder. It was concluded that the phrenic nerve communicating branch may be considered as another option to neurotize the suprascapular nerve.

Al-Qattan, M. M.; El-Sayed, A. A. F.

2014-01-01

16

Characterization of a chondroitin sulfate hydrogel for nerve root regeneration  

NASA Astrophysics Data System (ADS)

Brachial plexus injury is a serious medical problem that affects many patients annually, with most cases involving damage to the nerve roots. Therefore, a chondroitin sulfate hydrogel was designed to both serve as a scaffold for regenerating root neurons and deliver neurotrophic signals. Capillary electrophoresis showed that chondroitin sulfate has a dissociation constant in the micromolar range with several common neurotrophins, and this was determined to be approximately tenfold stronger than with heparin. It was also revealed that nerve growth factor exhibits a slightly stronger affinity for hyaluronic acid than for chondroitin sulfate. However, E8 chick dorsal root ganglia cultured in the presence of nerve growth factor revealed that ganglia cultured in chondroitin sulfate scaffolds showed more robust growth than those cultured in control gels of hyaluronic acid. It is hypothesized that, despite the stronger affinity of nerve growth factor for hyaluronic acid, chondroitin sulfate serves as a better scaffold for neurite outgrowth, possibly due to inhibition of growth by hyaluronic acid chains.

Conovaloff, Aaron; Panitch, Alyssa

2011-10-01

17

Bilateral phasic increases in dorsal root ganglia nerve growth factor synthesis after unilateral sciatic nerve crush.  

PubMed

The amount of nerve growth factor (NGF) in the L5, L6, and cervical dorsal root ganglia of rats was examined from 1 to 30 days after a unilateral crush lesion of the sciatic nerve and adjacent branches of the lumbar plexus at the level of the sciatic notch. Unilateral nerve crush produced increases in NGF content of lumbar ganglia at 1, 4, and 7-8 days after injury, with increased NGF mRNA at 4 and 7-8 days. Increases in NGF at 1 and 4 days were most pronounced on the unlesioned side while increases at days 7 and 8 were most pronounced on the lesioned side. NGF content increased in cervical ganglia of nerve-lesioned animals at 3 and 7 days after injury and in lumbar and cervical ganglia of sham-operated animals 3-5 days after surgery, with no comparable changes in NGF mRNA. Elevations of ganglionic NGF coincide temporally with some of the alterations in metabolism and morphology which occur in dorsal root ganglion neurons after sciatic nerve crush. However, the bilateral nature of increases in NGF demonstrates that the factor(s) producing the response is not restricted to ganglia axotomized by the injury. The data suggest that ganglionic NGF may be regulated by systemic factors, produced during stress or trauma, as well as by factors from the denervated target tissue and/or regenerating axons. PMID:7843302

Wells, M R; Vaidya, U; Schwartz, J P

1994-01-01

18

The European Spine Society AcroMed Prize 1994. Acute thermal nerve root injury.  

PubMed

Bone cement is sometimes used for vertebral body reconstruction following tumor removal. During such procedures, the polymerization of the methyl-metacrylate in the bone cement generates heat. Such temperature increase might cause damage to the nerve roots within the spinal canal. In the present study, pig cauda equina nerve roots were subjected to controlled temperature increases by means of a heat-generating probe. A temperature of 40 degrees C applied for 5 min did not cause any changes in nerve root function. However, 70 degrees C resulted in a complete block of nerve root function within 5 min. Histological nerve fiber damage was seen after exposure to 60 degrees C and 70 degrees C. The present study provides basic knowledge of heat-resistance properties of spinal nerve roots that might be directly applicable as guidelines for safety margins during surgical spine reconstruction procedures using bone cement. PMID:7866856

Konno, S; Olmarker, K; Byröd, G; Nordborg, C; Strömqvist, B; Rydevik, B

1994-01-01

19

Visualization of Sacral Nerve Roots via Percutaneous Intraspinal Navigation (PIN)? V  

Microsoft Academic Search

Summary: A percutaneous technique for visualizing sacral nerve roots is described. A fiberscope was inserted into the subarachnoid space through a sheath that was inserted via a percutaneous lumbar puncture. The sacral nerve roots were identified with endoscopic visualization and x-ray fluoroscopy localization of the endoscope. These images were compared with those obtained from a videoscope, which revealed better imaging.

Takuya Fujimoto; Brian P. Giles; Robert E. Replogle; Hitomi Fujimoto; Susan L. Miller; Phillip D. Purdy

20

Lumbar nerve root compression by synovial cysts of the ligamentum flavum. Report of four cases.  

PubMed

Synovial cysts of the ligamentum flavum, measuring 1 cm in diameter, caused compression of the lumbar nerve roots in four patients. The authors discuss the association of these cysts with advanced focal spondylosis, and speculate on their etiology. PMID:6699708

Abdullah, A F; Chambers, R W; Daut, D P

1984-03-01

21

Redundant Nerve Roots of Cauda Equina Mimicking Intradural Disc Herniation: A Case Report  

PubMed Central

Redundant Nerve Roots (RNRs) is an uncommon clinical condition characterized by a tortuous, serpentine, large and elongated nerve root of the cauda equina. To our knowledge, most cases of RNRs are associated with lumbar stenosis, and RNRs associated with lumbar disc herniation has not been reported until now. Here we present a rare case of unusual RNRs associated with lumbar disc herniation mimicking intradural disc herniation.

Yang, Sang Mi; Park, Hyung Ki; Cho, Sung Jin

2013-01-01

22

Fibrous adhesive entrapment of lumbosacral nerve roots as a cause of sciatica  

Microsoft Academic Search

Study design: Report of seven patients with fibrous adhesive entrapment of lumbosacral nerve roots as a cause of sciatica, whose radiographic findings were negative and who experienced relief from sciatica immediately after the entrapment was released.Objectives: To describe a new clinical entity of fibrous adhesive entrapment of lumbosacral nerve roots with negative radiographic findings.Setting: Orthopaedic department, Japan.Methods: Clinical evaluation and

K Ido; H Urushidani

2001-01-01

23

Nucleus pulposus-induced nerve root injury: effects of diclofenac and ketoprofen  

Microsoft Academic Search

Main problem. Nucleus pulposus and\\/or chronic compression can induce spinal nerve root injury. Inflammation has been proposed as having major importance in the pathophysiologic mechanisms involved in the induction of such injuries. Corticosteroids, potent anti-inflammatory drugs, have been demonstrated to reduce nucleus pulposus-induced spinal nerve root injury. The aim of the present study was to assess the effects of two

M. Cornefjord; K. Olmarker; K. Otani; B. Rydevik

2002-01-01

24

Results of treatment of trigeminal neuralgia by microvascular decompression of the Vth nerve at its root entry zone.  

PubMed

Eighty five patients suffering from trigeminal neuralgia resistant to medical therapy underwent surgical treatment for relief of pain at the Department of Neurosurgery University Alexander Hospital Sofia from 1981 until 1997. Microvascular decompression at the root entry zone of the V(th) nerve has been performed using the technique of Jannetta. The operative exploration of the parapontine root entry zone disclosed neurovascular conflicts in 87.1% of the cases. They represented displacement and/or distortion, sometimes pressure grooves, discoloration, altered vascularity of the V(th) nerve. The analysis of early postoperative results have shown an excellent outcome in 90.6% of the cases, good in 3.5% and poor in 2.4% with mortality of 3.5% early in these series when no postoperative monitoring was available. The follow up study one year after surgery revealed 90.2% excellent and 3.7% good results and poor outcome and recurrences in 6.1% of the cases. Patients with long lasting trigeminal neuralgia, previous destructive procedures, venous compression, lack of convincible evidences for neurovascular conflicts had less favorable outcome or recurrences. In the last years partial sensory rhizotomy was performed in cases when no neurovascular conflicts were found out. Patients with unquestionable arterial compression leading to displacement associated with distortion and pressure grooves had excellent outcomes. Early recurrences were associated with missed pathology at the entry zones. During reexplorations for late recurrences new arterial compression was found in less than half of the cases. PMID:10441061

Romansky, K; Stoianchev, N; Dinev, E; Iliev, I

1998-12-01

25

Neurophysiological changes in spinal nerve roots subjected to tensile loading at several strain rates  

Microsoft Academic Search

\\u000aSpinal nerve roots have been implicated in many types of traumatic injuries such as motor vehicle accidents, falls, and sports injury, causing damage to brachial plexus and lumbosacral plexus. They have also been involved in lower back pain, disc herniation or protrusions, sciatica, and traumatic birth delivers such as shoulder dystocia. These roots undergo tension, resulting in traumatic axonal injury

Gurjiwan Singh Virk

2012-01-01

26

The Relation Between Rotation Deformity and Nerve Root Stress in Lumbar Scoliosis  

NASA Astrophysics Data System (ADS)

Even though several finite element models of lumbar spine were introduced, there has been no model including the neural structure. Therefore, the authors made the novel lumbar spine finite element model including neural structure. Using this model, we investigated the relation between the deformity pattern and nerve root stress. Two lumbar models with different types of curve pattern (lateral bending and lateral bending with rotation curve) were made. In the model of lateral bending curves without rotation, the principal compressive nerve root stress on the concave side was greater than the principal tensile stress on the convex side at the apex vertebra. Contrarily, in the lateral bending curve with rotational deformity, the nerve stress on the convex side was higher than that on the concave side. Therefore, this study elicit that deformity pattern could have significantly influence on the nerve root stress in the lumbar spine.

Kim, Ho-Joong; Lee, Hwan-Mo; Moon, Seong-Hwan; Chun, Heoung-Jae; Kang, Kyoung-Tak

27

Cranial roots of the accessory nerve exist in the majority of adult humans.  

PubMed

The inclusion of a cranial root as a component of the accessory nerve is controversial with at least one recent study claiming that intracranial rootlets do not exist in humans. In response to this debate, the present study aimed to clarify this anatomy in a large cadaveric sample. In this study, 43 adult cadavers (86 sides) were dissected via a posterior approach to the craniocervical junction. Observations were made for the presence or absence of cranial roots of the accessory nerve, and when present, their lengths and diameters were measured. Relationships of these rootlets were documented. A cranial root of the accessory nerve was identified in 76% of sides. When identified, 1-6 cranial rootlets (mean 4.5) of the accessory nerve were observed. They ranged in diameter from 0.1 to 1.1 mm (mean 0.7 mm). The length of these nerves ranged from 8 to 24 mm with a mean of 17 mm. In general, the more superior rootlets were shorter and the more inferior rootlets were longer. Although there was a slight tendency for the cranial roots to be more numerous and larger on right sides and in males, this did not reach statistical significance. We believe this to be the largest study to date documenting the presence of a cranial root of the accessory nerve. Based on our findings, a cranial root exists in the majority of specimens. Neurosurgical procedures or high quality imaging of this area should enable the physician to see these structures. PMID:22855423

Tubbs, R Shane; Benninger, Brion; Loukas, Marios; Cohen-Gadol, Aaron A

2014-01-01

28

Development of a duration threshold for modulating evoked neuronal responses after nerve root compression injury.  

PubMed

Cervical nerve roots are susceptible to compression injuries of various durations. The duration of an applied compression has been shown to contribute to both the onset of persistent pain and also the degree of spinal cellular and molecular responses related to nociception. This study investigated the relationship between peripherally-evoked activity in spinal cord neurons during a root compression and the resulting development of axonal damage. Electrically-evoked spikes were measured in the spinal cord as a function of time during and after (post-compression) a 15 minute compression of the C7 nerve root. Compression to the root significantly (p=0.035) reduced the number of spikes that were evoked over time relative to sham. The critical time for compression to maximally reduce evoked spikes was 6.6±3.0 minutes. A second study measured the post- compression evoked neuronal activity following compression applied for a shorter, sub-threshold time (three minutes). Ten minutes after compression was removed, the discharge rate remained significantly (p=0.018) less than baseline by 58±25% relative to sham after the 15 minute compression, but returned to within 3±33% of baseline after the three minute compression. Axonal damage was evident in the nerve root at day seven after nerve root compression only after a 15 minute compression. These studies demonstrate that even a transient mechanical insult to the nerve root is sufficient to induce sustained neuronal dysfunction and axonal pathology associated with pain, and results provide support that such minor neural tissue traumas can actually induce long-lasting functional deficits. PMID:22869302

Nicholson, Kristen J; Quindlen, Julia C; Winkelstein, Beth A

2011-11-01

29

Controlled Release of GDNF Reduces Nerve Root-Mediated Behavioral Hypersensitivity  

PubMed Central

Nerve root compression produces persistent behavioral sensitivity in models of painful neck injury. This study utilized degradable poly(ethylene glycol) hydrogels to deliver glial cell line-derived neurotrophic factor (GDNF) to an injured nerve root. Hydrogels delivered ?98% of encapsulated GDNF over 7 days in an in vitro release assay without the presence of neurons and produced enhanced outgrowth of processes in cortical neural cell primary cultures. The efficacy of a GDNF hydrogel placed on the root immediately after injury was assessed in a rat pain model of C7 dorsal root compression. Control groups included painful injury followed by: (1) vehicle hydrogel treatment (no GDNF), (2) a bolus injection of GDNF, or (3) no treatment. After injury, mechanical allodynia (n=6/group) was significantly decreased with GDNF delivered by the hydrogel compared to the three injury control groups (p<0.03). The bolus GDNF treatment did not reduce allodynia at any time point. The GDNF receptor (GFR?-1) decreased in small, nociceptive neurons of the affected dorsal root ganglion, suggesting a decrease in receptor expression following injury. GDNF receptor immunoreactivity was significantly greater in these neurons following GDNF hydrogel treatment relative to GDNF bolus treated and untreated rats (p<0.05). These data suggest efficacy for degradable hydrogel delivery of GDNF and support this treatment approach for nerve root-mediated pain.

Hubbard, Raymond D.; Martinez, Joan J.; Burdick, Jason A.; Winkelstein, Beth A.

2008-01-01

30

A conduction block in sciatic nerves can be detected by magnetic motor root stimulation.  

PubMed

Useful diagnostic techniques for the acute phase of sciatic nerve palsy, an entrapment neuropathy, are not well established. The aim of this paper is to demonstrate the diagnostic utility of magnetic sacral motor root stimulation for sciatic nerve palsy. We analyzed the peripheral nerves innervating the abductor hallucis muscle using both electrical stimulations at the ankle and knee and magnetic stimulations at the neuro-foramina and conus medullaris levels in a patient with sciatic nerve palsy at the level of the piriformis muscle due to gluteal compression related to alcohol consumption. On the fourth day after onset, magnetic sacral motor root stimulation using a MATS coil (the MATS coil stimulation method) clearly revealed a conduction block between the knee and the sacral neuro-foramina. Two weeks after onset, needle electromyography supported the existence of the focal lesion. The MATS coil stimulation method clearly revealed a conduction block in the sciatic nerve and is therefore a useful diagnostic tool for the abnormal neurophysiological findings associated with sciatic nerve palsy even at the acute phase. PMID:23809191

Matsumoto, Hideyuki; Konoma, Yuko; Fujii, Kengo; Hanajima, Ritsuko; Terao, Yasuo; Ugawa, Yoshikazu

2013-08-15

31

Altered Function of Lumbar Nerve Roots in Patients With Transitional Lumbosacral Vertebrae  

Microsoft Academic Search

STUDY DESIGN: A retrospective study was conducted on the preoperative neurologic symptoms of patients with lumbar herniated discs. OBJECTIVE: To evaluate the possibility that the muscle innervation pattern and the sensory dermatomes of lumbar nerve roots are altered when a lumbosacral transitional vertebra is present. SUMMARY OF BACKGROUND DATA: In 1962, McCulloch et al suggested with intraoperative recordings that the

Han Soo Chang; Hiroshi NAKAGAWA

2004-01-01

32

A sciatic nerve with three roots and its perforation by the enlarged ischiadic artery.  

PubMed

Knowledge about the variations of the sciatic nerve (SN) is important for many medical science disciplines. Its compression, entrapment or injury of any kind can result in loss of sensation, pain or motor disabilities in the lower limbs. We observed concurrent neurovascular variations in the gluteal region of an adult female cadaver. The SN had three roots as it emerged out of the greater sciatic foramen. The upper root passed above the piriformis; the middle and lower roots passed below the piriformis. The three roots joined to form the SN in the gluteal region. The inferior gluteal artery (IGA) was large, and it passed below the piriformis, between the middle and lower root of the SN. After a tortuous course, this artery continued down as the sciatic/ischiadic artery. The ischiadic artery (IA) was large in size and pierced the SN in the thigh. After piercing the nerve, it terminated by dividing into muscular branches. The inferior gluteal nerve emerged out from the pelvis through the greater sciatic foramen, above the level of the piriformis. The SN in this case was highly predisposed to compression by the piriformis, IGA or IA, which in turn may lead to altered cutaneous sensation or weakness of the muscles. PMID:23959929

Nayak, Satheesha B; George, Bincy M; Mishra, Snigdha

2014-03-01

33

Predominant Patterns of Median Nerve Displacement and Deformation during Individual Finger Motion in Early Carpal Tunnel Syndrome.  

PubMed

Idiopathic carpal tunnel syndrome (CTS) is a common neuropathy, yet the pathologic changes do not explain the fleeting dynamic symptoms. Dynamic nerve-tendon interaction may be a contributing factor. Based on dynamic ultrasonographic examination of the carpal tunnel, we quantified nerve-tendon movement in thumb, index finger and middle finger flexion in normal subjects and those with mild-idiopathic CTS. Predominant motion patterns were identified. The nerve consistently moves volar-ulnarly. In thumb and index finger flexion, the associated tendons move similarly, whereas the tendon moves dorsoradially in middle finger flexion. Nerve displacement and deformation increased from thumb to index finger to middle finger flexion. Predomination motion patterns may be applied in computational simulations to prescribe specific motions to the tendons and to observe resultant nerve pressures. By identification of the greatest pressure-inducing motions, CTS treatment may be better developed. Symptomatic subjects displayed reduced nerve movement and deformation relative to controls, elucidating the physiologic changes that occur during mild CTS. PMID:24785444

Liong, Kyrin; Lahiri, Amitabha; Lee, Shujin; Chia, Dawn; Biswas, Arijit; Lee, Heow Pueh

2014-08-01

34

Macrophage-Mediated Dorsal Root Ganglion Damage Precedes Altered Nerve Conduction in SIV-Infected Macaques  

PubMed Central

Peripheral neuropathy is the most common neurological complication of HIV-1 infection, affecting over one-third of infected individuals, including those treated with antiretroviral therapy. To study the pathogenesis of HIV-induced peripheral nervous system disease, we established a model in which SIV-infected macaques developed changes closely resembling alterations reported in components of the sensory pathway in HIV-infected individuals. Significant declines in epidermal nerve fiber density developed in SIV-infected macaques, similar to that of HIV-infected individuals with neuropathy. Changes in dorsal root ganglia (DRG) included macrophage infiltration, SIV replication in macrophages, immune activation of satellite cells, and neuronal loss. To determine whether dorsal root ganglion damage was associated with altered nerve function, we measured unmyelinated C-fiber conduction velocities (CV) in nerves of SIV-infected macaques and compared CV changes with DRG alterations. Twelve weeks postinoculation, SIV-infected macaques had significantly lower C-fiber conduction velocity in sural nerves than uninfected animals and the magnitude of conduction velocity decline correlated strongly with extent of DRG macrophage infiltration. Thus, injury to neurons in the DRG—mediated by activated macrophages—preceded altered conduction of unmyelinated nerve fibers in SIV-infected macaques, suggesting that macrophage-mediated DRG damage may be the initiating event in HIV-induced sensory neuropathy.

Laast, Victoria A.; Shim, Beom; Johanek, Lisa M.; Dorsey, Jamie L.; Hauer, Peter E.; Tarwater, Patrick M.; Adams, Robert J.; Pardo, Carlos A.; McArthur, Justin C.; Ringkamp, Matthias; Mankowski, Joseph L.

2011-01-01

35

Diffusion tensor imaging and T2 relaxometry of bilateral lumbar nerve roots: feasibility of in-plane imaging.  

PubMed

Lower back pain is a common problem frequently encountered without specific biomarkers that correlate well with an individual patient's pain generators. MRI quantification of diffusion and T2 relaxation properties may provide novel insight into the mechanical and inflammatory changes that occur in the lumbosacral nerve roots in patients with lower back pain. Accurate imaging of the spinal nerve roots is difficult because of their small caliber and oblique course in all three planes. Two-dimensional in-plane imaging of the lumbosacral nerve roots requires oblique coronal imaging with large field of view (FOV) in both dimensions, resulting in severe geometric distortions using single-shot echo planar imaging (EPI) techniques. The present work describes initial success using a reduced-FOV single-shot spin-echo EPI acquisition to obtain in-plane diffusion tensor imaging (DTI) and T2 mapping of the bilateral lumbar nerve roots at the L4 level of healthy subjects, minimizing partial volume effects, breathing artifacts and geometric distortions. A significant variation in DTI and T2 mapping metrics is also reported along the course of the normal nerve root. The fractional anisotropy is statistically significantly lower in the dorsal root ganglia (0.287?±?0.068) than in more distal regions in the spinal nerve (0.402?±?0.040) (p?root ganglia (78.0?±?11.9?ms) than in more distal regions in the spinal nerve (59.5?±?7.4?ms) (p?nerve root DTI and T2 properties using the proposed methodology may identify the specific site of any degenerative and inflammatory changes along the nerve roots of patients with lower back pain. PMID:23208676

Karampinos, Dimitrios C; Melkus, Gerd; Shepherd, Timothy M; Banerjee, Suchandrima; Saritas, Emine U; Shankaranarayanan, Ajit; Hess, Christopher P; Link, Thomas M; Dillon, William P; Majumdar, Sharmila

2013-06-01

36

Intra-operative identification of conjoined lumbosacral nerve roots: a report of three cases.  

PubMed

We report 3 cases of conjoined nerve root anomalies identified during micro-endoscopic discectomy (MED). Between 2009 and 2010, 61 men and 20 women aged 18 to 84 (mean, 42) years underwent MED for symptomatic lumbar disc herniation of L3-4 (n=1), L4-5 (n=44), and L5-S1 (n=36). Magnetic resonance imaging (MRI), myelogram, and postmyelo computed tomography did not identify the anomalies. All 3 patients were male and had type 2A S1 conjoined nerve roots, with a herniated disc at L5-S1. None of them had any preoperative pseudolocalising neurological signs, but all demonstrated stiffer positive straight leg raise sign and deterioration of the Achilles tendon reflex. Postoperatively, all 3 patients achieved excellent clinical outcomes. PMID:22535819

Morishita, Yuichiro; Ohta, Hideki; Matsumoto, Yoshiyuki; Shiba, Keiichiro; Naito, Masatoshi

2012-04-01

37

Pleural malignant mesothelioma causing cord infiltration through the nerve root. Case report.  

PubMed

A 61-year-old man presented with a rare pleural malignant mesothelioma of the spine manifesting as progressive weakness of the bilateral lower extremities, numbness in the body and both legs, and dysfunction of the bladder and bowel. He had previous occupational exposure to asbestos while working at a car repair shop and had undergone right panpleuropneumonectomy under a diagnosis of sarcomatous type mesothelioma in the right pleural space. Magnetic resonance imaging of the spine with gadolinium showed an enhanced intramedullary tumor at the T4 level. Operative findings disclosed the clouded and swollen right posterior nerve root, and the pial surface was covered by clouded arachnoid-like membrane. The removed part of the T4 posterior nerve root and intramedullary tumor revealed malignant mesothelioma with invasion spreading along the posterior nerve root. He died of respiratory failure 3 months after the diagnosis. This case shows that spinal metastasis must be considered if a patient with pleural malignant mesothelioma shows neurological worsening and neuroimaging shows an abnormal lesion in the thoracic spinal cord. However, the patient's neurological condition is very difficult to improve in the presence of spinal cord infiltration. PMID:19398862

Okura, Hidehiro; Suga, Yasuo; Akiyama, Osamu; Kudo, Kentaro; Tsutsumi, Satoshi; Abe, Yusuke; Yasumoto, Yukimasa; Ito, Masanori; Izumi, Hiroshi; Shiomi, Kazu

2009-04-01

38

The potential for salmon fibrin and thrombin to mitigate pain subsequent to cervical nerve root injury  

PubMed Central

Nerve root compression is a common cause of radiculopathy and induces persistent pain. Mammalian fibrin is used clinically as a coagulant but presents a variety of risks. Fish fibrin is a potential biomaterial for neural injury treatment because it promotes neurite outgrowth, is non-toxic, and clots readily at lower temperatures. This study administered salmon fibrin and thrombin following nerve root compression and measured behavioral sensitivity and glial activation in a rat pain model. Fibrin and thrombin each significantly reduced mechanical allodynia compared to injury alone (p<0.02). Painful compression with fibrin exhibited allodynia that was not different from sham for any day using stimulation by a 2 g filament; allodynia was only significantly different (p<0.043) from sham using the 4 g filament on days 1 and 3. By day 5, responses for fibrin treatment decreased to sham levels. Allodynia following compression with thrombin treatment were unchanged from sham at any time point. Macrophage infiltration at the nerve root and spinal microglial activation were only mildly modified by salmon treatments. Spinal astrocytic expression decreased significantly with fibrin (p<0.0001) but was unchanged from injury responses for thrombin treatment. Results suggest that salmon fibrin and thrombin may be suitable biomaterials to mitigate pain.

Weisshaar, Christine L.; Winer, Jessamine P.; Guarino, Benjamin B.; Janmey, Paul A.; Winkelstein, Beth A.

2011-01-01

39

Gene profiling during development and after a peripheral nerve traumatism reveals genes specifically induced by injury in dorsal root ganglia  

Microsoft Academic Search

In order to shed light on transcriptional networks involved in adult peripheral nerve repair program, we propose for the first time an organization of the transcriptional dynamics of the mouse dorsal root ganglia (DRG) following a sciatic nerve lesion. This was done by a non-hierarchical bioinformatical clustering of four Serial Analysis of Gene Expression libraries performed on DRG at embryonic

Ilana Méchaly; Steeve Bourane; David Piquemal; Mohammed Al-Jumaily; Stéphanie Ventéo; Sylvie Puech; Frédérique Scamps; Jean Valmier; Patrick Carroll

2006-01-01

40

Rapid identification of anterior and posterior root of cauda equina nerves by near-infrared diffuse reflectance spectroscopy  

NASA Astrophysics Data System (ADS)

A new rapid chemometric method has been developed to identify the anterior and posterior roots of cauda equina nerves by near-infrared (NIR) diffuse reflectance spectroscopy. NIR spectra of nerves were measured using a Fourier transform NIR spectrometer equipped with a fiber-optic probe. The result revealed no observable difference in the spectra between the anterior and posterior root samples, but the two roots could be identified by cluster analysis based on the differences of their spectral features. The overall accuracy of the cluster analysis model was 87.5%, and the accuracy for the actual anterior root and actual posterior root were 95% and 80%, respectively. The result suggested that NIR spectroscopy in combination with the chemometrics method (cluster analysis) could be used to classify the anterior and posterior roots of cauda equina nerves. The proposed method required only a few minutes, while classical methods commonly required at least one hour. It was demonstrated that the new method could provide a rapid, correct, nondestructive and low-cost potential means to quickly differentiate anterior and posterior roots in mixed cauda equina nerves, which would be helpful for surgeons to align nerve stumps correctly.

Xie, Shaofei; Xiang, Bingren; Bu, Shoushan; Cao, Xiaojian; Ye, Ye; Lu, Jun; Deng, Haishan

2009-03-01

41

Surgical treatment options and management strategies of metastatic renal cell carcinoma to the lumbar spinal nerve roots.  

PubMed

Spinal nerve root metastasis of renal cell carcinoma is a rare occurrence. In addition to treatment of the primary lesion, surgical resection of the nerve root metastasis, occasionally with sacrifice of the involved nerve, is the accepted standard of treatment. Resection often resolves presenting motor and pain symptoms due to relief of neural compression. We describe two patients with nerve root metastasis of renal cell carcinoma and their management. While locally advanced and metastatic renal cell carcinoma has been shown to be chemo- and radio-resistant, immunotherapy is a promising treatment. Given the high prevalence of systemic disease in patients with intradural metastases, systemic (and possibly intracranial) imaging can be used to identify other potential areas of disease. PMID:23931936

Strong, Christian; Yanamadala, Vijay; Khanna, Arjun; Walcott, Brian P; Nahed, Brian V; Borges, Lawrence F; Coumans, Jean-Valery C E

2013-11-01

42

Inflammation in dorsal root ganglia after peripheral nerve injury: Effects of the sympathetic innervation.  

PubMed

Following a peripheral nerve injury, a sterile inflammation develops in sympathetic and dorsal root ganglia (DRGs) with axons that project in the damaged nerve trunk. Macrophages and T-lymphocytes invade these ganglia where they are believed to release cytokines that lead to hyperexcitability and ectopic discharge, possibly contributing to neuropathic pain. Here, we examined the role of the sympathetic innervation in the inflammation of L5 DRGs of Wistar rats following transection of the sciatic nerve, comparing the effects of specific surgical interventions 10-14days prior to the nerve lesion with those of chronic administration of adrenoceptor antagonists. Immunohistochemistry was used to define the invading immune cell populations 7days after sciatic transection. Removal of sympathetic activity in the hind limb by transecting the preganglionic input to the relevant lumbar sympathetic ganglia (ipsi- or bilateral decentralization) or by ipsilateral removal of these ganglia with degeneration of postganglionic axons (denervation), caused less DRG inflammation than occurred after a sham sympathectomy. By contrast, denervation of the lymph node draining the lesion site potentiated T-cell influx. Systemic treatment with antagonists of ?1-adrenoceptors (prazosin) or ?-adrenoceptors (propranolol) led to opposite but unexpected effects on infiltration of DRGs after sciatic transection. Prazosin potentiated the influx of macrophages and CD4(+) T-lymphocytes whereas propranolol tended to reduce immune cell invasion. These data are hard to reconcile with many in vitro studies in which catecholamines acting mainly via ?2-adrenoceptors have inhibited the activation and proliferation of immune cells following an inflammatory challenge. PMID:24418114

McLachlan, Elspeth M; Hu, Ping

2014-05-01

43

[Spontaneous nerve root cerebrospinal fluid leaks and intracranial hypotension: case report].  

PubMed

Spontaneous intracranial hypotension is a rare syndrome, characterized by pressure in the cerebrospinal fluid ranging between 50 and 70 mmH2O and postural headache. Its diagnosis is made through the clinical presentation, measurement of the cerebrospinal fluid pressure and neurorimage features. The clinical recognition of this pathology has been increasing and the differential diagnosis must be made with inflammatory meningeal processes and tumor. We report a case of spontaneous nerve root cerebrospinal fluid leaks in a 34 year-old man and intracranial hypotension. A literature review was performed evaluating the clinical, diagnostic and therapeutic aspects of this unusual pathology. PMID:12715038

Falavigna, Asdrubal; Ferraz, Fernando Antonio Patriani; Boscato, Giovana; Shimokawa, Marcos

2003-03-01

44

Cervical nerve root decompression by lateral approach as salvage operation after failed anterior transdiscal surgery: technical case report  

PubMed Central

Cervical nerve root compression caused by disco-osteophytic changes is classically operated by anterior transdiscal approach with disc replacement. If compression persists or recurs, reoperation via the same surgical route may be difficult, because of scar tissue and/or implants. An alternative approach may be necessary. We recommend the lateral cervical approach (retrojugular) as salvage operation in such cases. We report a patient with cervical nerve root compression operated by anterior transdiscal approach with plate and bone graft. As some compression persisted clinically and radiologically, the patient was re-operated via a lateral approach. The surgical access was free of scar tissue. The arthrodesis could be left intact and did not prevent effective nerve root decompression. The patient became asymptomatic. The lateral cervical approach (retrojugular) as reported here, is an excellent alternative pathway if reoperation after anterior transdiscal surgery with disc replacement becomes necessary.

George, Bernard

2009-01-01

45

Microsurgical anatomy of the denticulate ligaments and their relationship with the axilla of the spinal nerve roots.  

PubMed

The denticulate ligaments (DL), 20 or 21 pairs of meningeal extensions, spread from the lateral aspect of the spinal cord to the internal aspect of the spinal dura mater. The aim of this study is to define the specific relationship of the DL with adjacent axilla of the spinal nerve roots and to investigate the anatomical features of the DLs and their variations. The topographical anatomy of the DLs and their relationships with the adjacent axilla of the spinal nerve roots was examined on 16 formalin-fixed adult cadaveric spinal cords. The distances from the dural attachment of the DL to the axilla of the superior and inferior spinal nerve roots were measured bilaterally at every spinal level. Also the distances from the dural attachment of the DL to the lateral aspect of the spinal cord were measured bilaterally. Cervical DLs showed a triangular shape, while in the thoracic segment the ligament changes the shape to "Y." Also the most caudal DL was identified to be at the L1-2 level. Our study revealed that the distances from the dural attachment of the DL to the superior and inferior spinal nerve root axilla were different at the cervical, upper thoracic and the lower thoracic segments. Both distances to the superior and inferior spinal nerve root axilla were shown to increase from cervical to lower thoracic segments. This study provides a detailed anatomy of the DLs and their relationship with the adjacent spinal nerve root axilla. Clin. Anat. 27:733-737, 2014. © 2013 Wiley Periodicals, Inc. PMID:23897545

Gürer, Bora; Canbay, Suat; Bozkurt, Melih; Cikla, Ula?; Hananya, Tomer; Okut, Hayrettin; Ba?kaya, Mustafa K

2014-07-01

46

The comparative performance of Roots type aircraft engine superchargers as affected by change in impeller speed and displacement  

NASA Technical Reports Server (NTRS)

This report presents the results of tests made on three sizes of roots type aircraft engine superchargers. The impeller contours and diameters of these machines were the same, but the length were 11, 8 1/4, and 4 inches, giving displacements of 0.509, 0.382, and 0.185 cubic foot per impeller revolution. The information obtained serves as a basis for the examination of the individual effects of impeller speed and displacement on performance and of the comparative performance when speed and displacement are altered simultaneously to meet definite service requirements. According to simple theory, when assuming no losses, the air weight handled and the power required for a given pressure difference are directly proportional to the speed and the displacement. These simple relations are altered considerably by the losses. When comparing the performance of different sizes of machines whose impeller speeds are so related that the same service requirements are met, it is found that the individual effects of speed and displacement are canceled to a large extent, and the only considerable difference is the difference in the power losses which decrease with increase in the displacement and the accompanying decrease in speed. This difference is small in relation to the net power of the engine supercharger unit, so that a supercharger with short impellers may be used in those applications where the space available is very limited with any considerable sacrifice in performance.

Ware, Marsden; Wilson, Ernest E

1929-01-01

47

Ventral root re-implantation is better than peripheral nerve transplantation for motoneuron survival and regeneration after spinal root avulsion injury  

PubMed Central

Background Peripheral nerve (PN) transplantation and ventral root implantation are the two common types of recovery operations to restore the connection between motoneurons and their target muscles after brachial plexus injury. Despite experience accumulated over the past decade, fundamental knowledge is still lacking concerning the efficacy of the two microsurgical interventions. Methods Thirty-eight adult female Sprague–Dawley rats were divided into 5 groups. Immediately following root avulsion, animals in the first group (n?=?8) and the second group (n?=?8) received PN graft and ventral root implantation respectively. The third group (n?=?8) and the fourth group (n?=?8) received PN graft and ventral root implantation respectively at one week after root avulsion. The fifth group received root avulsion only as control (n?=?6). The survival and axonal regeneration of severed motoneurons were investigated at 6 weeks post-implantation. Results Re-implantation of ventral roots, both immediately after root avulsion and in delay, significantly increased the survival and regeneration of motoneurons in the avulsed segment of the spinal cord as compared with PN graft transplantation. Conclusions The ventral root re-implantation is a better surgical repairing procedure than PN graft transplantation for brachial plexus injury because of its easier manipulation for re-implanting avulsed ventral roots to the preferred site, less possibility of causing additional damage and better effects on motoneuron survival and axonal regeneration.

2013-01-01

48

The Accuracy of the Physical Examination for the Diagnosis of Midlumbar and Low Lumbar Nerve Root Impingement  

PubMed Central

Study Design Cross-sectional study with prospective recruitment. Objective To determine the accuracy of the physical examination for the diagnosis of midlumbar nerve root impingement (L2, L3, or L4), low lumbar nerve root impingement (L5 or S1) and level-specific lumbar nerve root impingement on magnetic resonance imaging (MRI), using individual tests and combinations of tests. Summary of Background Data The sensitivity and specificity of the physical examination for the localization of nerve root impingement has not been previously studied. Methods Sensitivities, specificities and LRs were calculated for the ability of individual tests and test combinations to predict the presence or absence of nerve root impingement at midlumbar, low lumbar, and specific nerve root levels. Results LRs ?5.0 indicate moderate to large changes from pre-test probability of nerve root impingement to post-test probability. For the diagnosis of midlumbar impingement, the femoral stretch test (FST), crossed femoral stretch test (CFST), medial ankle pinprick sensation, and patellar reflex testing demonstrated LRs ?5.0 (LR ?). LRs ?5.0 were seen with the combinations of FST and either patellar reflex testing (LR 7.0; 95% CI 2.3–21), or the sit-to-stand test (LR ?). For the diagnosis of low lumbar impingement, the Achilles reflex test demonstrated a LR ?5.0 (LR 7.1; CI 0.96–53); test combinations did not increase LRs. For the diagnosis of level-specific impingement, LRs ?5.0 were seen for anterior thigh sensation at L2 (LR 13; 95% CI 1.8–87); FST at L3 (LR 5.7 ; 95% CI 2.3–4.4); patellar reflex testing (LR 7.7; 95% CI 1.7–35), medial ankle sensation (LR ?), or CFST (LR 13; 95% CI 1.8–87) at L4; and hip abductor strength at L5(LR 11; 95% CI 1.3–84). Test combinations increased LRs for level-specific root impingement at the L4 level only. Conclusions Individual physical examination tests may provide clinical information which substantially alters the likelihood that midlumbar impingement, low lumbar impingement, or level-specific impingement is present. Test combinations improve diagnostic accuracy for midlumbar impingement.

Suri, Pradeep; Rainville, James; Katz, Jeffrey N.; Jouve, Cristin; Hartigan, Carol; Limke, Janet; Pena, Enrique; Li, Ling; Swaim, Bryan; Hunter, David J

2010-01-01

49

Pituitary adenylate cyclase activating peptide expression in the rat dorsal root ganglia: Up-regulation after peripheral nerve injury  

Microsoft Academic Search

Pituitary adenylate cyclase activating peptide (PACAP) is expressed in a population of capsaicin-sensitive primary sensory neurons of small to medium size in the rat. In the present report we have examined the effect of sciatic nerve injury (unilateral transection) on PACAP expression (immunocytochemistry, radioimmunoassay, in situ hybridization and northern blot analysis) in dorsal root ganglia at the lumbar level and

Y.-Z. Zhang; J. Hannibal; Q. Zhao; K. Moller; N. Danielsen; J. Fahrenkrug; F. Sundler

1996-01-01

50

Cervical Radiculopathy (Pinched Nerve)  

MedlinePLUS

... American Academy of Orthopaedic Surgeons. Cervical Radiculopathy (Pinched Nerve) Some people have neck pain that may radiate ... an injury near the root of a spinal nerve. A nerve root injury is sometimes referred to ...

51

Paresis of the L5 nerve root after reduction of low-grade lumbosacral dysplastic spondylolisthesis: a case report.  

PubMed

We present a unique case of a 16-year-old patient who underwent lumbar decompression surgery (L4-S1), low-grade spondylolisthesis reduction surgery at L5-S1, and posterior instrumented fusion from L4 to the pelvis. Neurologic monitoring did not show any sustained changes throughout the operation. The patient was awoken from endotracheal anesthesia with grade 0 muscle function of the left extensor hallucis longus and tibialis anterior muscles resulting in left-sided foot drop. At the last follow-up 12 months after surgery, the patient had partial recovery, with grade 4 muscle function of the left extensor hallucis longus and tibialis anterior muscles. We suggest that early identification with direct nerve root stimulation and wake-up test immediately after reduction of spondylolisthesis will allow prompt release of the reduction and further foramen exploration, and increase the possibility of good postoperative nerve root recovery. PMID:24887052

Lykissas, Marios G; Aichmair, Alexander; Widmann, Roger; Sama, Andrew A

2014-09-01

52

C5 nerve root palsy following decompression of the cervical spine: a systematic evaluation of the literature.  

PubMed

C5 nerve root palsy is a rare and potentially debilitating complication of cervical spine surgery. Currently, however, there are no guidelines to help surgeons to prevent or treat this complication. We carried out a systematic review of the literature to identify the causes of this complication and options for its prevention and treatment. Searches of PubMed, Embase and Medline yielded 60 articles for inclusion, most of which addressed C5 palsy as a complication of surgery. Although many possible causes were given, most authors supported posterior migration of the spinal cord with tethering of the nerve root as being the most likely. Early detection and prevention of a C5 nerve root palsy using neurophysiological monitoring and variations in surgical technique show promise by allowing surgeons to minimise or prevent the incidence of C5 palsy. Conservative treatment is the current treatment of choice; most patients make a full recovery within two years. Cite this article: Bone Joint J 2014;96-B:950-5. PMID:24986950

Guzman, J Z; Baird, E O; Fields, A C; McAnany, S J; Qureshi, S A; Hecht, A C; Cho, S K

2014-07-01

53

Transverse Process and Needles of Medial Branch Block to Facet Joint as Landmarks for Ultrasound-Guided Selective Nerve Root Block  

PubMed Central

Background Selective lumbar nerve root block (SNRB) is generally accepted as an effective treatment method for back pain with sciatica. However, it requires devices producing radioactive materials such as C-arm fluoroscopy. This study evaluated the usefulness of the longitudinal view of transverse process and needles for medial branch block as landmarks under ultrasonography. Methods We performed selective nerve root block for 96 nerve roots in 61 patients under the guidance of ultrasound. A curved probe was used to identify the facet joints and transverse processes. Identifying the lumbar nerve roots under the skin surface and ultrasound landmarks, the cephalad and caudal medial branch blocks were undertaken under the transverse view of sonogram first. A needle for nerve root block was inserted between the two transverse processes under longitudinal view, while estimating the depth with the needle for medial branch block. We then injected 1.0 mL of contrast medium and checked the distribution of the nerve root with C-arm fluoroscopy to evaluate the accuracy. The visual analog scale (VAS) was used to access the clinical results. Results Seven SNRBs were performed for the L2 nerve root, 15 for L3, 49 for L4, and 25 for L5, respectively. Eighty-six SNRBs (89.5%) showed successful positioning of the needles. We failed in the following cases: 1 case for the L2 nerve root; 2 for L3; 3 for L4; and 4 for L5. The failed needles were positioned at wrong leveled segments in 4 cases and inappropriate place in 6 cases. VAS was improved from 7.6 ± 0.6 to 3.5 ± 1.3 after the procedure. Conclusions For SNRB in lumbar spine, the transverse processes under longitudinal view as the ultrasound landmark and the needles of medial branch block to the facet joint can be a promising guidance.

Kim, Daehee; Choi, Donghyuk; Kim, Chungyoung; Kim, Jeongseok

2013-01-01

54

Gene profiling during development and after a peripheral nerve traumatism reveals genes specifically induced by injury in dorsal root ganglia.  

PubMed

In order to shed light on transcriptional networks involved in adult peripheral nerve repair program, we propose for the first time an organization of the transcriptional dynamics of the mouse dorsal root ganglia (DRG) following a sciatic nerve lesion. This was done by a non-hierarchical bioinformatical clustering of four Serial Analysis of Gene Expression libraries performed on DRG at embryonic day E13, neonatal day P0, adult and adult 3 days post-sciatic nerve section. Grouping genes according to their expression profiles shows that a combination of down-regulation of genes expressed at the adult stages, re-expression of embryonic genes and induction of a set of de novo genes takes place in injured neurons. Focusing on this latter event highlights Ddit3, Timm8b and Oazin as potential new injury-induced molecular actors involved in a stress response pathway. Their association with the traumatic state was confirmed by real-time PCR and in situ hybridization investigations. Clustering analysis allows us to distinguish developmental re-programming events from nerve-injury-induced processes and thus provides a basis for molecular understanding of transcriptional alterations taking place in the DRG after a sciatic nerve lesion. PMID:16769221

Méchaly, Ilana; Bourane, Steeve; Piquemal, David; Al-Jumaily, Mohammed; Ventéo, Stéphanie; Puech, Sylvie; Scamps, Frédérique; Valmier, Jean; Carroll, Patrick

2006-07-01

55

The topography of root fibres within the sciatic nerve trunk of the dog.  

PubMed Central

The architecture of the fibres in the sciatic nerve of the dog has been analysed by following the degeneration of fibres resulting from division of the individual spinal nerves which contribute to the sciatic nerve. A pattern has been demonstrated which varies in part with the size of the contribution to the sciatic nerve from each of the spinal nerves L6, L7 and S1. The redistribution of the fibres of each spinal nerve to form the various branches of the sciatic nerve is also described, and the significance of these arrangements is discussed. Images Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14

Ueyama, T

1978-01-01

56

Modified pathological classification of brachial plexus root injury and its MR imaging characteristics.  

PubMed

The authors described a modified pathological classification (PC) of brachial plexus injury (BPI) and its magnetic resonance (MR) imaging characteristics. The reliability and diagnostic accuracy of MR imaging for detecting nerve injury was discussed. Between 2006 and 2010, 86 patients with BPI were managed surgically in our department. Their preoperative MR images and surgical findings were analyzed retrospectively. The PC of BPI was classified into five types: (I) nerve root injury in continuity (including Sunderland grade I-IV injury); (II) postganglionic spinal nerve rupture with or without proximal stump; (III) preganglionic root injury (visible); (IV) preganglionic nerve root injury and postganglionic spinal nerves injury; (V) preganglionic root injury (invisible). The main MR imaging characteristics of BPI included traumatic meningocele, displacement of spinal cord, the absence of nerve root, "Black line" sign, nerve root/trunk injury in continuity, and thickening and edema of nerve root. The accuracy of MR imaging for detecting C5, C6, C7, C8, and T1 nerve roots injury were 93.3, 95.2, 92.3, 84, and 74.4%, respectively. The modified PC provides a detailed description of nerve root injury in BPI, and MR imaging technique is a reliable method for detecting nerve root injury. PMID:24163228

Yang, Jiantao; Qin, Bengang; Fu, Guo; Li, Ping; Zhu, Qingtang; Liu, Xiaolin; Zhu, Jiakai; Gu, Liqiang

2014-03-01

57

Subdural spread of injected local anesthetic in a selective transforaminal cervical nerve root block: a case report  

PubMed Central

Introduction Although uncommon, selective cervical nerve root blocks can have serious complications. The most serious complications that have been reported include cerebral infarction, spinal cord infarction, transient quadriplegia and death. Case presentation A 40-year-old Japanese woman with a history of severe right-sided cervical radicular pain was scheduled to undergo a right-sided C6 selective cervical nerve root block using a transforaminal approach under fluoroscopic guidance. An anterior oblique view of the C5-C6 intervertebral foramen was obtained, and a 23-gauge spinal needle, connected to the normal extension tube with a syringe filled with contrast medium, was introduced into the posterior-caudal aspect of the C5-C6 intervertebral foramen on the right side. In the anteroposterior view, the placement of the needle was considered satisfactory when it was placed no more medial than halfway across the width of the articular pillar. Although the spread of the contrast medium along the C6 nerve root was observed with right-sided C6 radiculography, the subdural flow of the contrast medium was not observed with real-time fluoroscopy. The extension tube used for the radiculography was removed from the spinal needle and a normal extension tube with a syringe filled with lidocaine connected in its place. We performed a negative aspiration test and then injected 1.5?mL of 1.0% lidocaine slowly around the C6 nerve root. Immediately after the injection of the local anesthetic, our patient developed acute flaccid paralysis, complained of breathing difficulties and became unresponsive; her respiratory pattern was uncoordinated. After 20 minutes, she regained consciousness and became alert, and her muscle strength in all four limbs returned to normal without any sensory deficits after receiving emergent cardiorespiratory support. Conclusions We believe that confirming maintenance of the appropriate needle position in the anteroposterior view by injecting local anesthetic is important for preventing central needle movement. Because the potential risk of serious complications cannot be completely eliminated during the use of any established selective cervical nerve root block procedure, preparation for an emergency airway, ventilation and cardiovascular support is indispensable in cases of high spinal cord anesthesia.

2012-01-01

58

Blood-nerve barrier: distribution of anionic sites on the endothelial plasma membrane and basal lamina of dorsal root ganglia.  

PubMed

Previous investigations of the blood-nerve barrier have correlated the greater permeability of ganglionic endoneurial vessels, compared to those of nerve trunks, with the presence of fenestrations and open intercellular junctions. Recent studies have demonstrated reduced endothelial cell surface charge in blood vessels showing greater permeability. To determine the distribution of anionic sites on the plasma membranes and basal laminae of endothelial cells in dorsal root ganglia, cationic colloidal gold and cationic ferritin were used. Electron microscopy revealed the existence of endothelial microdomains with differing labelling densities. Labelling indicated that caveolar and fenestral diaphragms and basal laminae are highly anionic at physiological pH, luminal plasma membranes and endothelial processes are moderately charged and abluminal plasma membranes are weakly anionic. Tracers did not occur in caveolae or cytoplasmic vesicles. In vitro tracer experiments at pH values of 7.3, 5.0, 3.5 and 2.0 indicated that the anionic charge on the various endothelial domains was contributed by chemical groups with differing pKa values. In summary, the labelling of ganglionic and sciatic nerve vessels was similar except for the heavy labelling of diaphragms in a minority of endoneurial vessels in ganglia. This difference is likely to account in part for the greater permeability of ganglionic endoneurial vessels. The results are discussed with regard to the blood-nerve and -brain barriers and vascular permeability in other tissues and a comparison made between the ultrastructure and anionic microdomains of epi-, peri- and endoneurial vessels of dorsal root ganglia and sciatic nerves. PMID:1960538

Bush, M S; Reid, A R; Allt, G

1991-09-01

59

Surgical treatment of bifid mental nerve damaged by root canal therapy. A case report.  

PubMed

This article describes the successful surgical treatment of a case of damage to the inferior alveolar nerve, due to inadvertent extrusion of endodontic material into the mandibular canal. The accident was favoured by an anatomical variant of the nerve canal ending with a double mental foramen, already described in the literature. The complex surgical operation of uncertain outcome was dictated by neuralgia refractory to medical treatment, rather than hypoesthesia associated with compression of the nerve trunk. Problems related to loss of sensitivity and possible causes of nerve damage (traumatic, pathological and iatrogenic) are discussed. PMID:18784636

Lorenzini, G; Viviano, M; Di Vece, L; Parrini, S; Autelitano, L; Biglioli, F

2008-01-01

60

TRPC4 in rat dorsal root ganglion neurons is increased after nerve injury and is necessary for neurite outgrowth.  

PubMed

Canonical transient receptor potential (TRPC) receptors are Ca(2+)-permeable cation channels that have a variety of physiological functions and may be involved in neuronal development and plasticity. We investigated the expression profile of TRPC channels in adult rat dorsal root ganglia (DRG) after nerve injury and examined the role of TRPC4 in neurite outgrowth in cultured DRG neurons. Sciatic nerve transection and microinjection of dibutyryl cAMP were employed to induce axonal regeneration in vivo. TRPC4 mRNA was significantly increased whereas TRPC1, TRPC3, TRPC6, and TRPC7 remained unaltered after nerve injury or dibutyryl-cAMP microinjection. The increases in TRPC4 transcript and protein were transient with maximal levels reached at 2 or 7 days, respectively. In addition, TRPC4 transcript in ND7/23 and NDC cells, hybrid cell lines derived from neonatal DRG and neuroblastoma, was substantially increased on differentiation, characterized by neurite outgrowth. In adult DRG, TRPC4 immunoreactivity was found in small and large neurons, and nerve injury increased the number of TRPC4-immunoreactive cells, particularly in large neurons. TRPC4 immunoreactivity was present in growth cones at various stages of DRG neurite outgrowth in vitro. Suppression of TRPC4 by a specific small interfering RNA or antisense significantly reduced the length of neurites in cultured DRG neurons. Expression of short hairpin RNA significantly down-regulated TRPC4 protein level and shortened neurite lengths in differentiated ND7/23 cells. The reduction in neurite lengths in ND7/23 cells was rescued by overexpression of human TRPC4. Our results suggest that TRPC4 contributes to axonal regeneration after nerve injury. PMID:17928298

Wu, Dongsheng; Huang, Wenlong; Richardson, Peter M; Priestley, John V; Liu, Min

2008-01-01

61

CNS-derived glia ensheath peripheral nerves and mediate motor root development  

PubMed Central

Motor function requires that motor axons extend from the spinal cord at regular intervals and that they are myelinated by Schwann cells. Little attention has been given to another cellular structure, the perineurium, which ensheaths the motor nerve, forming a flexible, protective barrier. Consequently, the origin of perineurial cells and their roles in motor nerve formation are poorly understood. Using time-lapse imaging in zebrafish, we show that perineurial cells are born in the CNS, arising as ventral spinal-cord glia before migrating into the periphery. In embryos lacking perineurial glia, motor neurons inappropriately migrated outside of the spinal cord and had aberrant axonal projections, indicating that perineurial glia carry out barrier and guidance functions at motor axon exit points. Additionally, reciprocal signaling between perineurial glia and Schwann cells was necessary for motor nerve ensheathment by both cell types. These insights reveal a new class of CNS-born glia that critically contributes to motor nerve development.

Kucenas, Sarah; Takada, Norio; Park, Hae-Chul; Woodruff, Elvin; Broadie, Kendal; Appel, Bruce

2009-01-01

62

Surgical management of first caudal nerve root foraminal compression secondary to intervertebral disc disease in a Cocker Spaniel.  

PubMed

A nine-year-old spayed female Cocker Spaniel was investigated for an eight week history of licking and rubbing at the tail base, dullness, and signs of pain on manipulation of the tail. Left-sided intraforaminal compression of the first caudal nerve root due to intervertebral disc disease was diagnosed by radiographic, computed tomography, and magnetic resonance imaging examinations. The dog was nonresponsive to conservative medical therapy. A decompressive left-sided first-second caudal (Cd1-Cd2) foraminotomy was performed. Postoperative computed tomography confirmed surgical decompression of the involved nerve root. At the one month follow-up examination there was marked improvement in clinical signs. At two months, clinical signs were completely resolved and there was not any evidence of recurrence twelve months after surgery. Intervertebral disc disease should be considered as a differential diagnosis in dogs with discomfort at the tail base or signs of pain on manipulation of the tail. Surgical decompression may be indicated for management of these cases. This is the first report of diagnosis and surgical management of caudal intervertebral disc disease by foraminotomy in the dog. Surgical decompression by foraminotomy may therefore be a treatment option for this condition. PMID:22105313

de Vicente, F; Pinilla, M; McConnell, J F; Bernard, F

2012-01-01

63

The evaluation of liquid crystal thermography in the investigation of nerve root compression due to lumbosacral lateral spinal stenosis.  

PubMed

The role of liquid crystal thermography (LCT) in the investigation of nerve root compression due to lumbosacral lateral spinal stenosis was evaluated using a quantitative analysis technique. In 28 healthy volunteers, normal lower limb dermatomal asymmetry was found to follow a Gaussian distribution, with a normal range of less than 1.0 degree for the lower limbs and less than 1.9 degrees for the feet. The results of LCT from a patient group were compared with those from other investigations, with the following results: clinical assessment (107 patients), 53% agreement; myelography (60 patients), 45% agreement; computerized tomography (35 patients), 46% agreement; electromyography (27 patients), 41% agreement; and surgical findings (19 patients), 53% agreement. Each method of investigation was compared against the surgeon's final overall assessment. Clinical assessment agreed in 76%, myelography in 71%, computerized tomography in 71%, and electromyography in 70%. However, agreement could be demonstrated in only 48% of cases using LCT; therefore, it would appear that LCT is by far the least reliable of these techniques in the diagnosis of nerve root compression. PMID:3750079

Mills, G H; Davies, G K; Getty, C J; Conway, J

1986-06-01

64

Riluzole effects on behavioral sensitivity and the development of axonal damage and spinal modifications that occur after painful nerve root compression.  

PubMed

Object Cervical radiculopathy is often attributed to cervical nerve root injury, which induces extensive degeneration and reduced axonal flow in primary afferents. Riluzole inhibits neuro-excitotoxicity in animal models of neural injury. The authors undertook this study to evaluate the antinociceptive and neuroprotective properties of riluzole in a rat model of painful nerve root compression. Methods A single dose of riluzole (3 mg/kg) was administered intraperitoneally at Day 1 after a painful nerve root injury. Mechanical allodynia and thermal hyperalgesia were evaluated for 7 days after injury. At Day 7, the spinal cord at the C-7 level and the adjacent nerve roots were harvested from a subgroup of rats for immunohistochemical evaluation. Nerve roots were labeled for NF200, CGRP, and IB4 to assess the morphology of myelinated, peptidergic, and nonpeptidergic axons, respectively. Spinal cord sections were labeled for the neuropeptide CGRP and the glutamate transporter GLT-1 to evaluate their expression in the dorsal horn. In a separate group of rats, electrophysiological recordings were made in the dorsal horn. Evoked action potentials were identified by recording extracellular potentials while applying mechanical stimuli to the forepaw. Results Even though riluzole was administered after the onset of behavioral sensitivity at Day 1, its administration resulted in immediate resolution of mechanical allodynia and thermal hyperalgesia (p < 0.045), and these effects were maintained for the study duration. At Day 7, axons labeled for NF200, CGRP, and IB4 in the compressed roots of animals that received riluzole treatment exhibited fewer axonal swellings than those from untreated animals. Riluzole also mitigated changes in the spinal distribution of CGRP and GLT-1 expression that is induced by a painful root compression, returning the spinal expression of both to sham levels. Riluzole also reduced neuronal excitability in the dorsal horn that normally develops by Day 7. The frequency of neuronal firing significantly increased (p < 0.045) after painful root compression, but riluzole treatment maintained neuronal firing at sham levels. Conclusions These findings suggest that early administration of riluzole is sufficient to mitigate nerve root-mediated pain by preventing development of neuronal dysfunction in the nerve root and the spinal cord. PMID:24678596

Nicholson, Kristen J; Zhang, Sijia; Gilliland, Taylor M; Winkelstein, Beth A

2014-06-01

65

A literature review reveals that trials evaluating treatment of non-specific low back pain use inconsistent criteria to identify serious pathologies and nerve root involvement  

PubMed Central

Objectives The broad aim of this study was to assess the homogeneity of patients included in trials of non-specific low back pain (NSLBP). To do this, we investigated the consistency and clarity of criteria used to identify and exclude participants with serious pathologies and nerve root compromise in randomized controlled trials, investigating interventions for NSLBP. Methods We searched Medline database for randomized controlled trials of low back pain (LBP). published between 2000 and 2009. We then randomly selected and screened trials for inclusion until we had 50 eligible trials. Data were extracted on the criteria used to identify cases of serious conditions (e.g. cancer, fracture) and nerve root involvement. Results The majority of papers (35/50) explicitly excluded patients with serious pathology. However, the terminology used and examples given were highly variable. Nerve root involvement was an exclusion criterion in the majority but not all studies. The criteria used for excluding patients with nerve root involvement varied greatly between studies. The most common criteria were ‘motor, sensory or reflex changes’ (nine studies), followed by ‘pain radiating below the knee’ (five studies) and ‘reduced straight leg raise which reproduces leg pain’ (five studies). In half of the included studies, the criteria used, while alluding to nerve root involvement, were not explained adequately for us to determine the types of patients included or excluded. Discussion The inconsistent and unclear criteria used to identify cases of serious pathology and nerve root compromise means that published trials of LBP likely include heterogeneous patient populations. This trait limits our ability to make comparisons across trials or pool studies. Standardization and consensus is important for future research.

Williams, Ciaran; Hancock, Mark J; Ferreira, Manuela; Ferreira, Paulo; Maher, Chris G

2012-01-01

66

Intra-epidermal nerve fibres in human skin: back to the roots.  

PubMed

Regarding the existence and the role of intra-epidermal nerve fibres, the literature is ambiguous. However, performing a literature search, a landmark paper turned up that even many dermatologists seem to have forgotten, or may not even know at all. This paper is entitled 'The innervation of human epidermis' written by Arthur and Shelley (J Invest Dermatol, 32, 1959, 397). The full text is available via http://www.nature.com/jid/journal/v32/n3/pdf/jid195969a.pdf. The authors present data on intra-epidermal nerves at 16 representative body areas. The existence of intra-epidermal nerve fibres is undisputable and does not only explain clinical symptoms but may even provide a promising target for drug development. PMID:24450967

Abels, Christoph

2014-04-01

67

Effects of Ethyl Pyruvate on Allodynia, TNF-? Expression, and Apoptosis in the Dorsal Root Ganglion after Spinal Nerve Ligation Injury  

PubMed Central

Background It has been demonstrated that the expression of tumor necrosis factor-? (TNF-?) and apoptotic cell death in the dorsal root ganglion (DRG) following spinal nerve constriction injury play a role in the initiation and continuation of hyperalgesia and allodynia. The present study was designed to investigate the effects of ethyl pyruvate (EP) on mechanical and cold allodynia, TNF-? expression, and apoptosis in DRG after spinal nerve ligation injury. Methods Rats were divided into 3 groups: control, pre-EP, and post-EP. EP (50 mg/kg) was intraperitoneally injected 30 minutes before (pre-EP) or after (post-EP) surgery. Behavioral tests to determine mechanical and cold allodynia were conducted before surgery and 4 and 7 days after surgery. Seven days after surgery, TNF-? protein levels in DRG were evaluated by enzyme-linked immunosorbent assay, and DRG apoptosis was determined by immunohistochemical detection of activated caspase-3. Results Treatment with EP significantly reduced mechanical and cold allodynia following spinal nerve ligation injury. TNF-? protein levels in the pre-EP (4.7 ± 1.2 pg/200 µg; P < 0.001) and post-EP (6.4 ± 1.8 pg/200 µg; P < 0.001) groups were 2-3 times lower than the control group (14.4 ± 1.2 pg/200 µg). The percentages of neurons and satellite cells that co-localized with caspase-3 were also significantly lower in the pre-EP and post-EP groups than the control group. Conclusions These results demonstrate that EP has a strong anti-allodynic effect that acts through the inhibition of TNF-? expression and apoptosis in DRG after spinal nerve ligation injury.

Choi, Dae Kee; Shin, Jin Woo; Suh, Jeong Hun

2012-01-01

68

Persistence of attacks of cluster headache after trigeminal nerve root section  

Microsoft Academic Search

Summary Cluster headache is a strictly unilateral headache that occurs in association with cranial autonomic features. We report a patient with a trigeminal nerve section who continued to have attacks. A 59-year-old man described a 14-year history of left-sided episodes of excruciating pain centred on the retro-orbital and orbi- tal regions. These episodes lasted 1-4 h, recurring 2-3 times daily.

Manjit S. Matharu; Peter J. Goadsby

2002-01-01

69

Altered neuronatin expression in the rat dorsal root ganglion after sciatic nerve transection  

Microsoft Academic Search

BACKGROUND: Several molecular changes occur following axotomy, such as gene up-regulation and down-regulation. In our previous study using Affymetrix arrays, it was found that after the axotomy of sciatic nerve, there were many novel genes with significant expression changes. Among them, neuronatin (Nnat) was the one which expression was significantly up-regulated. Nnat was identified as a gene selectively expressed in

Kuan-Hung Chen; Chien-Hui Yang; Jiin-Tsuey Cheng; Chih-Hsien Wu; Wei-Dih Sy; Chung-Ren Lin

2010-01-01

70

Spinal intradural cystic venous angioma originating from a nerve root in the cauda equina.  

PubMed

A spinal intradural extramedullary venous angioma is extremely rare and has not been previously reported. In this paper, the authors report on this entity with morphological and immunohistochemical evidence, and discuss the surgical strategy for its treatment. A 54-year-old woman presented to Nagoya University Hospital complaining of left-sided pain in the hip, thigh, and inguinal and perianal regions, with progressive worsening during the previous 2 weeks. Lumbar spine MRI showed an intradural extramedullary cyst at the level of T12-L1, which extended from the conus medullaris to the cauda equina. The cyst wall was not enhanced on T1-weighted MRI with Gd. Intraoperatively, a midline dural opening allowed the authors to easily visualize a dark-reddish cyst behind the spinal nerve rootlets in the cauda equina adjacent to the conus medullaris. The cyst was believed to originate from one of the spinal nerve rootlets in the cauda equina and a cluster of veins was identified on the cyst wall. The cyst was resected with the affected nerve rootlet. The surgery left no detectable neurological deficit. Based on the morphological and immunohistochemical evidence, the lesion was diagnosed as a venous angioma. No tumor recurrence was confirmed based on MRI at the time of the 2-year follow up. This is the first report of an intradural extramedullary cystic venous angioma that was successfully resected. PMID:24093468

Nishimura, Yusuke; Hara, Masahito; Natsume, Atsushi; Nakajima, Yasuhiro; Fukuyama, Ryuichi; Wakabayashi, Toshihiko; Ginsberg, Howard J

2013-12-01

71

Sciatic nerve injury induces apoptosis of dorsal root ganglion satellite glial cells and selectively modifies neurosteroidogenesis in sensory neurons.  

PubMed

Neurosteroids are synthesized either by glial cells, by neurons, or within the context of neuron-glia cross-talk. Various studies suggested neurosteroid involvement in the control of neurodegeneration but there is no evidence showing that the natural protection of nerve cells against apoptosis directly depends on their own capacity to produce neuroprotective neurosteroids. Here, we investigated the interactions between neurosteroidogenesis and apoptosis occurring in sensory structures of rats subjected to neuropathic pain generated by sciatic nerve chronic constriction injury (CCI). Using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), we observed no apoptotic cells in the spinal cord up to 30 days after CCI although pain symptoms such as mechano-allodynia, thermal and mechanical hyperalgesia were evidenced with the Hargreaves's behavioral and von Frey filament tests. In contrast, double-labeling experiments combining TUNEL and immunostaining with antibodies against glutamine synthetase or neuronal nuclei protein revealed apoptosis occurrence in satellite glial cells (SGC) (not in neurons) of CCI rat ipsilateral dorsal root ganglia (DRG) at day 30 after injury. Pulse-chase experiments coupled with high performance liquid chromatography and flow scintillation detection showed that, among numerous biosynthetic pathways converting [(3)H]pregnenolone into various [(3)H]neurosteroids, only [(3)H]estradiol formation was selectively modified and upregulated in DRG of CCI rats. Consistently, immunohistochemical investigations localized aromatase (estradiol-synthesizing enzyme) in DRG neurons but not in SGC. Pharmacological inhibition of aromatase caused apoptosis of CCI rat DRG neurons. Altogether, our results suggest that endogenously produced neurosteroids such as estradiol may be pivotal for the protection of DRG sensory neurons against sciatic nerve CCI-induced apoptosis. PMID:19565659

Schaeffer, Véronique; Meyer, Laurence; Patte-Mensah, Christine; Eckert, Anne; Mensah-Nyagan, Ayikoe G

2010-01-15

72

Dermatomal somatosensory evoked potential demonstration of nerve root decompression after VAX-D therapy  

Microsoft Academic Search

Reductions in low back pain and referred leg pain associated with a diagnosis of herniated disc, degenerative disc disease or facet syndrome have previously been reported after treatment with a VAX-D table, which intermittently distracts the spine. The object of this study was to use dermatomal somatosensory evoked potentials (DSSEPs) to demonstrate lumbar root decompression following VAX-D therapy. Seven consecutive

William K. Naguszewski; Robert K. Naguszewski; Earl E. Gose

2001-01-01

73

Slowed motor conduction in lumbosacral nerve roots in cauda equina lesions: a new diagnostic technique  

Microsoft Academic Search

New techniques have been developed for the electrophysiological assessment of patients with suspected cauda equina lesions using transcutaneous spinal stimulation (500-1500 V: time constant 50 microseconds) to measure motor latencies to the external and sphincter and puborectalis muscles from L1 and L4 vertebral levels. These latencies represent motor conduction in the S3 and S4 motor roots of the cauda equina

M Swash; S J Snooks

1986-01-01

74

Vascularization of the dorsal root ganglia and peripheral nerve of the mouse: Implications for chemical-induced peripheral sensory neuropathies  

PubMed Central

Although a variety of industrial chemicals, as well as several chemotherapeutic agents used to treat cancer or HIV, preferentially induce a peripheral sensory neuropathy what remains unclear is why these agents induce a sensory vs. a motor or mixed neuropathy. Previous studies have shown that the endothelial cells that vascularize the dorsal root ganglion (DRG), which houses the primary afferent sensory neurons, are unique in that they have large fenestrations and are permeable to a variety of low and high molecular weight agents. In the present report we used whole-mount preparations, immunohistochemistry, and confocal laser scanning microscopy to show that the cell body-rich area of the L4 mouse DRG has a 7 fold higher density of CD31+ capillaries than cell fiber rich area of the DRG or the distal or proximal aspect of the sciatic nerve. This dense vascularization, coupled with the high permeability of these capillaries, may synergistically contribute, and in part explain, why many potentially neurotoxic agents preferentially accumulate and injure cells within the DRG. Currently, cancer survivors and HIV patients constitute the largest and most rapidly expanding groups that have chemically induced peripheral sensory neuropathy. Understanding the unique aspects of the vascularization of the DRG and closing the endothelial fenestrations of the rich vascular bed of capillaries that vascularize the DRG before intravenous administration of anti-neoplastic or anti-HIV therapies, may offer a mechanism based approach to attenuate these chemically induced peripheral neuropathies in these patients.

Jimenez-Andrade, Juan M; Herrera, Monica B; Ghilardi, Joseph R; Vardanyan, Marina; Melemedjian, Ohannes K; Mantyh, Patrick W

2008-01-01

75

Pulsed Radiofrequency of the Dorsal Root Ganglia is Superior to Pharmacotherapy or Pulsed Radiofrequency of the Intercostal Nerves in the Treatment of Chronic Postsurgical Thoracic Pain  

Microsoft Academic Search

pulsed RF of the intercostal nerves (ICN) and pulsed RF of the dorsal root ganglia (DRG) in CPTP. Methods: Retrospective data analy- sis involving 49 patients. Results: At 6-week follow-up, 61.5% of the pulsed RF DRG group reported ? 50% pain relief vs. 27.3% in the medical management (MM) group and 21.4% in the ICN group (P=0.12). At 3-month follow-up,

Steven P. Cohen; Anthony Sireci; Christopher L. Wu; Thomas M. Larkin; Kayode A. Williams; Robert W. Hurley

76

Spatio-temporal changes of SDF1 and its CXCR4 receptor in the dorsal root ganglia following unilateral sciatic nerve injury as a model of neuropathic pain  

Microsoft Academic Search

There is a growing evidence that chemokines and their receptors play a role in inducing and maintaining neuropathic pain.\\u000a In the present study, unilateral chronic constriction injury (CCI) of rat sciatic nerve under aseptic conditions was used\\u000a to investigate changes for stromal derived factor-1 (SDF1) and its CXCR4 receptor in lumbal (L4–L5) and cervical (C7–C8) dorsal\\u000a root ganglia (DRG) from

Petr Dubový; I. Klusáková; I. Svíženská; V. Brázda

2010-01-01

77

Differential Effects of Electrical Stimulation of Sciatic Nerve on Metabolic Activity in Spinal Cord and Dorsal Root Ganglion in the Rat  

Microsoft Academic Search

Electrical stimulation of the proximal stump of the transected sciatic nerve produces a frequency-dependent activation of glucose utilization, measured with the autoradiographic deoxy[14C]glucose method, in the dorsal horn of the spinal cord but produces no change in glucose utilization in the dorsal root ganglion cells. These results suggest that axon terminals and not the cell bodies are the sites of

Massako Kadekaro; Alison M. Crane; Louis Sokoloff

1985-01-01

78

Visualization of the Foramen Intervertebral Nerve Root of Cervical Spine with 3.0 Tesla Magnetic Resonance Imaging: A Comparison of Three-dimensional Acquisition Techniques.  

PubMed

Identification of the compression factor in cervical disc herniation and cervical spondylotic radioculopathy is often problematic when using two-dimensional magnetic resonance imaging (MRI). This prompted us to compare and examined three-dimensional sequences, coherent oscillatory state acquisition for the manipulation of image contrast (COSMIC), fast imaging employing steady state acquisition (FIESTA) and T2 star weighted MR angiography (SWAN) with 3.0-Tesla (T) MRI to visualize the foramen intervertebral nerve root for the cervical spine. Fat-suppressed COSMIC (FS-COSMIC) sequence gave the highest signal intensity ratio (1.85±0.06) of the nerve root and vertebral arch. A significant difference in signal intensity ratio of the nerve root was found between FS-COSMIC and FIESTA sequences. No significant difference was found between the FS-COSMIC and FIESTA sequences in the cerebrospinal fluid and the spinal cord. The FS-COSMIC sequence proved to be the most suitable sequence for intra and extra dura matter. PMID:25055947

Shishido, Hiroki; Takashima, Hiroyuki; Takebayashi, Tsuneo; Akatsuka, Yoshihiro; Imamura, Rui; Nagahama, Hiroshi; Shirase, Ryuzi

2014-07-01

79

The Impact of Spinal Cord Nerve Roots and Denticulate Ligaments on Cerebrospinal Fluid Dynamics in the Cervical Spine  

PubMed Central

Cerebrospinal fluid (CSF) dynamics in the spinal subarachnoid space (SSS) have been thought to play an important pathophysiological role in syringomyelia, Chiari I malformation (CM), and a role in intrathecal drug delivery. Yet, the impact that fine anatomical structures, including nerve roots and denticulate ligaments (NRDL), have on SSS CSF dynamics is not clear. In the present study we assessed the impact of NRDL on CSF dynamics in the cervical SSS. The 3D geometry of the cervical SSS was reconstructed based on manual segmentation of MRI images of a healthy volunteer and a patient with CM. Idealized NRDL were designed and added to each of the geometries based on in vivo measurments in the literature and confirmation by a neuroanatomist. CFD simulations were performed for the healthy and patient case with and without NRDL included. Our results showed that the NRDL had an important impact on CSF dynamics in terms of velocity field and flow patterns. However, pressure distribution was not altered greatly although the NRDL cases required a larger pressure gradient to maintain the same flow. Also, the NRDL did not alter CSF dynamics to a great degree in the SSS from the foramen magnum to the C1 level for the healthy subject and CM patient with mild tonsillar herniation (?6 mm). Overall, the NRDL increased fluid mixing phenomena and resulted in a more complex flow field. Comparison of the streamlines of CSF flow revealed that the presence of NRDL lead to the formation of vortical structures and remarkably increased the local mixing of the CSF throughout the SSS.

Heidari Pahlavian, Soroush; Yiallourou, Theresia; Tubbs, R. Shane; Bunck, Alexander C.; Loth, Francis; Goodin, Mark; Raisee, Mehrdad; Martin, Bryn A.

2014-01-01

80

Re-evaluation of the phenotypic changes in L4 dorsal root ganglion neurons after L5 spinal nerve ligation.  

PubMed

The L5 spinal nerve ligation (SNL) is a widely used animal neuropathic pain model. There are conflicting reports regarding the extent of injury to the L4 dorsal root ganglion (DRG) neurons in this model. If a significant number of these neurons were injured, the previously reported phenotypic and electrophysiological changes at this level are in need of re-evaluation by separating the injured neurons and the frankly spared ones. So, we immunostained activating transcription factor 3 (ATF3) and examined the change in expression of transcripts for neuropeptide Y (NPY), brain-derived neurotrophic factor (BDNF) and several voltage-gated sodium channel ?-subunits (Nav1.1, Nav1.3, Nav1.6, Nav1.7, Nav1.8, and Nav1.9) in the L4 DRG by comparing signal intensities of individual neurons using in situ hybridization histochemistry. ATF3-immunoreactivity was similarly observed in 4-6% of neuronal nuclei of the SNL and sham-operated ipsilateral L4 DRGs. Comparison between ATF3+ and ATF3- neurons in the SNL L4 DRG revealed that (1) whereas NPY induction occurred in ATF3+ cells, BDNF increased mainly in ATF3- neurons; (2) although ATF3+ neurons had higher Nav1.3 signals than ATF3- neurons, these signals were much lower than those of the L5 DRG neurons; and (3) ATF3+/N52- neurons selectively lost Nav1.8 and Nav1.9 mRNAs. Comparison of the total neuronal populations among naïve, SNL, and sham-operated rats revealed no significant differences for all examined Nav mRNAs. Because neuropathic pain behaviors were developed by rats with SNL but not the sham-operation, the small number of injured L4 neurons likely do not contribute to the pathomechanisms of neuropathic pain. PMID:22054598

Fukuoka, Tetsuo; Yamanaka, Hiroki; Kobayashi, Kimiko; Okubo, Masamichi; Miyoshi, Kan; Dai, Yi; Noguchi, Koichi

2012-01-01

81

The impact of spinal cord nerve roots and denticulate ligaments on cerebrospinal fluid dynamics in the cervical spine.  

PubMed

Cerebrospinal fluid (CSF) dynamics in the spinal subarachnoid space (SSS) have been thought to play an important pathophysiological role in syringomyelia, Chiari I malformation (CM), and a role in intrathecal drug delivery. Yet, the impact that fine anatomical structures, including nerve roots and denticulate ligaments (NRDL), have on SSS CSF dynamics is not clear. In the present study we assessed the impact of NRDL on CSF dynamics in the cervical SSS. The 3D geometry of the cervical SSS was reconstructed based on manual segmentation of MRI images of a healthy volunteer and a patient with CM. Idealized NRDL were designed and added to each of the geometries based on in vivo measurments in the literature and confirmation by a neuroanatomist. CFD simulations were performed for the healthy and patient case with and without NRDL included. Our results showed that the NRDL had an important impact on CSF dynamics in terms of velocity field and flow patterns. However, pressure distribution was not altered greatly although the NRDL cases required a larger pressure gradient to maintain the same flow. Also, the NRDL did not alter CSF dynamics to a great degree in the SSS from the foramen magnum to the C1 level for the healthy subject and CM patient with mild tonsillar herniation (?6 mm). Overall, the NRDL increased fluid mixing phenomena and resulted in a more complex flow field. Comparison of the streamlines of CSF flow revealed that the presence of NRDL lead to the formation of vortical structures and remarkably increased the local mixing of the CSF throughout the SSS. PMID:24710111

Heidari Pahlavian, Soroush; Yiallourou, Theresia; Tubbs, R Shane; Bunck, Alexander C; Loth, Francis; Goodin, Mark; Raisee, Mehrdad; Martin, Bryn A

2014-01-01

82

Depression of Ca2+/Calmodulin-Dependent Protein Kinase II in Dorsal Root Ganglion Neurons after Spinal Nerve Ligation  

PubMed Central

The enzyme calcium/calmodulin-dependent protein kinase II (CaMKII) is associated with memory and its ? isoform is critical for development of activity-induced synaptic changes. Therefore, we hypothesized that CaMKII is involved in altered function of dorsal root ganglion (DRG) neurons after neuronal injury. To test this hypothesis, Sprague–Dawley rats were made hyperalgesic by L5 and L6 spinal nerve ligation (SNL), and changes in total phosphorylated and unphosphorylated CaMKII (tCaMKII) and phosphorylated form of its ? isoform (pCaMKII?) were analyzed using immunochemistry in different subpopulations of DRG. SNL did not induce any changes in tCaMKII between experimental groups, while the overall percentage of pCaMKII?-positive neurons in injured L5 DRG SNL (24.8%) decreased significantly when compared to control (41.7%). SNL did not change the percentage of pCaMKII?/N52 colabeled neurons but decreased the percentage of N52-negative nonmyelinated neurons that expressed pCaMKII? from 27% in control animals to 11% after axotomy. We also observed a significant decrease in the percentage of small nonpeptidergic neurons labeled with IB4 (37.6% in control vs. 4.0% in L5 SNL DRG), as well as a decrease in the percentage of pCaMKII?/IB4 colabeled neurons in injured L5 DRGs (27% in control vs. 1% in L5 DRG of SNL group). Our results show that reduction in pCaMKII? levels following peripheral injury is due to the loss of IB4-positive neurons. These results indicate that diminished afferent activity after axotomy may lead to decreased phosphorylation of CaMKII?.

Kojundzic, Sanja Lovric; Puljak, Livia; Hogan, Quinn; Sapunar, Damir

2014-01-01

83

A temporal variation in nonneuronal protein synthesis in dorsal root ganglia and nerve and its significance to studies of axonal transport  

SciTech Connect

Protein synthesis and fast axonal transport were studied in vitro using dorsal root ganglia (DRG)-sciatic nerve preparations from the amphibian Xenopus laevis. It was observed that the rate of incorporation of (/sup 3/H)leucine into protein in DRG and isolated segments of nerve began to increase 9 to 11 h after killing the animal, attaining at 13 to 17 h a maximum of 5- to 10-times preincrease (less than 9 h) values. At the same time as an increase in the rate of incorporation began, synthesis commenced in DRG and nerve exposed to cycloheximide (125 micrograms/ml). Whereas cycloheximide reduced fast axonal transport to 1 to 3% of control values in preparations maintained 20 to 24 h in vitro, cycloheximide reduced incorporation in DRG to only 80% of control values. N-terminal labeling studies showed that both the increased incorporation and cycloheximide-insensitive incorporation resulted from protein synthesis. Autoradiographic and incorporation studies indicated that nonneuronal cells situated in the ganglion capsule and perineural sheath of the nerve were responsible for both the increased incorporation and cycloheximide-insensitive synthesis. The findings have implications for the study of axonal transport.

Snyder, R.E.; O'Brien, D.W.; Nihei, T.

1984-03-01

84

Monitoring of immune cell response to B cell depletion therapy and nerve root injury using SPIO enhanced MRI  

NASA Astrophysics Data System (ADS)

Magnetic resonance (MR) is a robust platform for non-invasive, high-resolution anatomical imaging. However, MR imaging lacks the requisite sensitivity and contrast for imaging at the cellular level. This represents a clinical impediment to greater diagnostic accuracy. Recent advances have allowed for the in vivo visualization of populations and even of individual cells using superparamagnetic iron oxide (SPIO) MR contrast agents. These nanoparticles, commonly manifested as a core of a single iron oxide crystal or cluster of crystals coated in a biocompatible shell, function to shorten proton relaxation times. In MR imaging these constructs locally dephase protons, resulting in a decrease in signal (hypointensity) localized to the region of accumulation of SPIO. In the context of immune cell imaging, SPIO can provide insight into the cellular migration patterns, trafficking, temporal dynamics and progression of diseases and their related pathological states. Furthermore, by visualizing the presence and activity of immune cells, SPIO-enabled cellular imaging can help evaluate the efficacy of therapy in immune disorders. This thesis examines the production, modification and application of SPIO in a range of in vitro and in vivo immune-response-relevant cellular systems. The role of different nanoparticle characteristics including diameter, surface charge and concentration are investigated in the labeling of T cells in culture. Following optimization of SPIO loading conditions for lymphocytes, the effect these particles have on the activation of primary B cells are elucidated. B cells are tracked using a variety of modalities, with and without the application of B cell depleting therapy. This is to evaluate the efficacy of SPIO as in vivo marker for B cell distribution. Unmodified SPIO were applied to monitor macrophage infiltration in a transient nerve root compression model, with implications for neck pain diagnosis and treatment. Nanoparticle accumulation and MR hypointensity was correlated to the presence of activated macrophage at the site of injury. Taken together, the application of SPIO to study nanoparticle uptake in vitro and visualization of immune cells in vivo provide a basis for advanced study and diagnosis of diverse pathologies.

Thorek, Daniel L.

85

Roots.  

PubMed

Many unicellular eukaryotic organisms possess complex fiber systems that organize and anchor the flagellar basal apparatus in the cell [20, 24]. In 1978 we first published the observation that one of these fiber systems, the striated flagellar root of the quadriflagellate green alga Tetraselmis subcordiformis (= Platymonas subcordiformis), is a contractile organelle [31]. We subsequently found that striated flagellar roots are composed, in part, of the Ca(2+)-binding protein centrin [30]. Since that time, centrin has been found to be a ubiquitous component of the flagellar basal apparatus, basal bodies and centrioles, and centrosomes and mitotic spindle poles of eukaryotic cells (for general reviews see [28, 34]). While we have learned a great deal about centrin from other organisms, our earliest success in understanding the biology of centrin was in large part due to the extraordinary extent to which Tetraselmis cells have elaborated their centrin-based organelles. In this paper, I will return attention to several unanswered questions concerning Tetraselmis striated flagellar root behavior and I will suggest several new directions that students may wish to pursue in order to tease fresh insights from this fascinating organism. PMID:9495031

Salisbury, J L

1998-01-01

86

Distribution of sensory neurones of the pudendal nerve in the dorsal root ganglia and their projection to the spinal cord  

Microsoft Academic Search

The morphology and distribution of the sensory neurones of the pudendal nerve within the spinal ganglia of rats were investigated by use of horseradish peroxidase (HRP). The labelling was visualized in diaminobenzidine (DAB) or tetramethyl-benzidine (TMB)-stained sections. Injection of HRP directly into the pudendal nerve labelled perikarya predominantly in the sixth lumbar DRG (L6). Following injection of HRP into the

D. C. M. Taylor; H.-W. Korf; Fr.-K. Pierau

1982-01-01

87

Virus-mediated shRNA knockdown of Na(v)1.3 in rat dorsal root ganglion attenuates nerve injury-induced neuropathic pain.  

PubMed

Neuropathic pain is a chronic condition that is often refractory to treatment with available therapies and thus an unmet medical need. We have previously shown that the voltage-gated sodium channel Na(v)1.3 is upregulated in peripheral and central nervous system (CNS) of rats following nerve injury, and that it contributes to nociceptive neuron hyperexcitability in neuropathic conditions. To evaluate the therapeutic potential of peripheral Na(v)1.3 knockdown at a specific segmental level, we constructed adeno-associated viral (AAV) vector expressing small hairpin RNA against rat Na(v)1.3 and injected it into lumbar dorsal root ganglion (DRG) of rats with spared nerve injury (SNI). Our data show that direct DRG injection provides a model that can be used for proof-of-principle studies in chronic pain with respect to peripheral delivery route of gene transfer constructs, high transduction efficiency, flexibility in terms of segmental localization, and limited behavioral effects of the surgical procedure. We show that knockdown of Na(v)1.3 in lumbar 4 (L4) DRG results in an attenuation of nerve injury-induced mechanical allodynia in the SNI model. Taken together, our studies support the contribution of peripheral Na(v)1.3 to pain in adult rats with neuropathic pain, validate Na(v)1.3 as a target, and provide validation for this approach of AAV-mediated peripheral gene therapy. PMID:22910296

Samad, Omar A; Tan, Andrew M; Cheng, Xiaoyang; Foster, Edmund; Dib-Hajj, Sulayman D; Waxman, Stephen G

2013-01-01

88

Neuronal calcium-binding proteins 1/2 localize to dorsal root ganglia and excitatory spinal neurons and are regulated by nerve injury.  

PubMed

Neuronal calcium (Ca(2+))-binding proteins 1 and 2 (NECAB1/2) are members of the phylogenetically conserved EF-hand Ca(2+)-binding protein superfamily. To date, NECABs have been explored only to a limited extent and, so far, not at all at the spinal level. Here, we describe the distribution, phenotype, and nerve injury-induced regulation of NECAB1/NECAB2 in mouse dorsal root ganglia (DRGs) and spinal cord. In DRGs, NECAB1/2 are expressed in around 70% of mainly small- and medium-sized neurons. Many colocalize with calcitonin gene-related peptide and isolectin B4, and thus represent nociceptors. NECAB1/2 neurons are much more abundant in DRGs than the Ca(2+)-binding proteins (parvalbumin, calbindin, calretinin, and secretagogin) studied to date. In the spinal cord, the NECAB1/2 distribution is mainly complementary. NECAB1 labels interneurons and a plexus of processes in superficial layers of the dorsal horn, commissural neurons in the intermediate area, and motor neurons in the ventral horn. Using CLARITY, a novel, bilaterally connected neuronal system with dendrites that embrace the dorsal columns like palisades is observed. NECAB2 is present in cell bodies and presynaptic boutons across the spinal cord. In the dorsal horn, most NECAB1/2 neurons are glutamatergic. Both NECAB1/2 are transported into dorsal roots and peripheral nerves. Peripheral nerve injury reduces NECAB2, but not NECAB1, expression in DRG neurons. Our study identifies NECAB1/2 as abundant Ca(2+)-binding proteins in pain-related DRG neurons and a variety of spinal systems, providing molecular markers for known and unknown neuron populations of mechanosensory and pain circuits in the spinal cord. PMID:24616509

Zhang, Ming-Dong; Tortoriello, Giuseppe; Hsueh, Brian; Tomer, Raju; Ye, Li; Mitsios, Nicholas; Borgius, Lotta; Grant, Gunnar; Kiehn, Ole; Watanabe, Masahiko; Uhlén, Mathias; Mulder, Jan; Deisseroth, Karl; Harkany, Tibor; Hökfelt, Tomas G M

2014-03-25

89

Neuronal expression of the ubiquitin ligase Nedd4-2 in rat dorsal root ganglia: modulation in the spared nerve injury model of neuropathic pain.  

PubMed

Neuronal hyperexcitability following peripheral nerve lesions may stem from altered activity of voltage-gated sodium channels (VGSCs), which gives rise to allodynia or hyperalgesia. In vitro, the ubiquitin ligase Nedd4-2 is a negative regulator of VGSC ?-subunits (Na(v)), in particular Na(v)1.7, a key actor in nociceptor excitability. We therefore studied Nedd4-2 in rat nociceptors, its co-expression with Na(v)1.7 and Na(v)1.8, and its regulation in pathology. Adult rats were submitted to the spared nerve injury (SNI) model of neuropathic pain or injected with complete Freund's adjuvant (CFA), a model of inflammatory pain. L4 dorsal root ganglia (DRG) were analyzed in sham-operated animals, seven days after SNI and 48 h after CFA with immunofluorescence and Western blot. We observed Nedd4-2 expression in almost 50% of DRG neurons, mostly small and medium-sized. A preponderant localization is found in the non-peptidergic sub-population. Additionally, 55.7 ± 2.7% and 55.0 ± 3.6% of Nedd4-2-positive cells are co-labeled with Na(v)1.7 and Na(v)1.8 respectively. SNI significantly decreases the proportion of Nedd4-2-positive neurons from 45.9 ± 1.9% to 33.5 ± 0.7% (p<0.01) and the total Nedd4-2 protein to 44% ± 0.13% of its basal level (p<0.01, n=4 animals in each group, mean ± SEM). In contrast, no change in Nedd4-2 was found after peripheral inflammation induced by CFA. These results indicate that Nedd4-2 is present in nociceptive neurons, is downregulated after peripheral nerve injury, and might therefore contribute to the dysregulation of Na(v)s involved in the hyperexcitability associated with peripheral nerve injuries. PMID:23022218

Cachemaille, M; Laedermann, C J; Pertin, M; Abriel, H; Gosselin, R-D; Decosterd, I

2012-12-27

90

Linalool blocks excitability in peripheral nerves and voltage-dependent Na + current in dissociated dorsal root ganglia neurons  

Microsoft Academic Search

Linalool is a terpene that occurs as a major constituent of essential oils of many plants of widespread distribution. It possesses several biological and pharmacological activities, including depressant effects on the central nervous system and olfactory receptors. The present study investigated whether linalool affects the excitability of peripheral components of the somatic sensory system. We used sciatic nerve and preparations

José Henrique Leal-Cardoso; Kerly Shamyra da Silva-Alves; Francisco Walber Ferreira-da-Silva; Tiago dos Santos-Nascimento; Humberto Cavalcante Joca; Flávio Henrique Pequeno de Macedo; Pedro Militão de Albuquerque-Neto; Pedro Jorge Caldas Magalhães; Saad Lahlou; Jader Santos Cruz; Roseli Barbosa

2010-01-01

91

Contribution of TRPV1 receptor-expressing fibers to spinal ventral root after-discharges and mechanical hyperalgesia in a spared nerve injury (SNI) rat model.  

PubMed

Neuropathic pain induces allodynia and hyperalgesia. In the spared nerve injury (SNI) model, marked mechanical hyperalgesia is manifested as prolongation of the duration of paw withdrawal after pin stimulation. We have previously reported that spinal ventral root discharges (after-discharges) after cessation of noxious mechanical stimulation applied to the corresponding hindpaw were prolonged in anesthetized spinalized rats. Since these after-discharges occurred through transient receptor potential (TRP) V1-positive fibers, these fibers could contribute to mechanical hyperalgesia. Therefore, we examined whether selective deletion of TRPV1-positive fibers by resiniferatoxin, an ultrapotent TRPV1 agonist, would affect the behavioral changes and ventral root discharges in SNI rats. Mechanical allodynia in the von Frey test, mechanical hyperalgesia after pin stimulation, and enhancement of ventral root discharges, but not thermal hyperalgesia in the plantar test, appeared in Wistar rats with SNI. Mechanical hyperalgesia was abolished by treatment with resiniferatoxin, whereas mechanical allodynia was not affected. Moreover, resiniferatoxin eliminated after-discharges completely. These results show that TRPV1-positive fibers do not participate in the mechanical allodynia caused by sensitization of A?-fibers, but contribute to the enhancement of after-discharges and mechanical hyperalgesia following SNI. It is suggested that the mechanisms responsible for generating mechanical allodynia differ from those for prolongation of mechanical hyperalgesia. PMID:23238537

Yamamoto, Shohei; Ohsawa, Masahiro; Ono, Hideki

2013-01-01

92

Electromechanical Nerve Stimulator  

NASA Technical Reports Server (NTRS)

Nerve stimulator applies and/or measures precisely controlled force and/or displacement to nerve so response of nerve measured. Consists of three major components connected in tandem: miniature probe with spherical tip; transducer; and actuator. Probe applies force to nerve, transducer measures force and sends feedback signal to control circuitry, and actuator positions force transducer and probe. Separate box houses control circuits and panel. Operator uses panel to select operating mode and parameters. Stimulator used in research to characterize behavior of nerve under various conditions of temperature, anesthesia, ventilation, and prior damage to nerve. Also used clinically to assess damage to nerve from disease or accident and to monitor response of nerve during surgery.

Tcheng, Ping; Supplee, Frank H., Jr.; Prass, Richard L.

1993-01-01

93

Rescue of alpha-SNS sodium channel expression in small dorsal root ganglion neurons after axotomy by nerve growth factor in vivo.  

PubMed

Small (18-25 microm diam) dorsal root ganglion (DRG) neurons are known to express high levels of tetrodotoxin-resistant (TTX-R) sodium current and the mRNA for the alpha-SNS sodium channel, which encodes a TTX-R channel when expressed in oocytes. These neurons also preferentially express the high affinity receptor for nerve growth factor (NGF), TrkA. Levels of TTX-R sodium current and of alpha-SNS mRNA are reduced in these cells after axotomy. To determine whether NGF participates in the regulation of TTX-R current and alpha-SNS mRNA in small DRG neurons in vivo, we axotomized small lumbar DRG neurons by sciatic nerve transection and administered NGF or Ringer solution to the proximal nerve stump using osmotic pumps. Ten to 12 days after pump implant, whole cell patch-clamp recording demonstrated that TTX-R current density was decreased in Ringer-treated axotomized neurons (154 +/- 45 pA/pF; mean +/- SE) compared with nonaxotomized control neurons (865 +/- 123 pA/pF) and was restored partially toward control levels in NGF-treated axotomized neurons (465 +/- 78 pA/pF). The V1/2 for steady-state activation and inactivation of TTX-R currents were similar in control, Ringer- and NGF-treated axotomized neurons. Reverse transcription polymerase chain reaction revealed an upregulation of alpha-SNS mRNA levels in NGF-treated compared with Ringer-treated axotomized DRG. In situ hybridization showed that alpha-SNS mRNA levels were decreased significantly in small Ringer-treated axotomized DRG neurons in vivo and also in small DRG neurons that were dissociated and maintained in vitro, so as to correspond to the patch-clamp conditions. NGF-treated axotomized neurons had a significant increase in alpha-SNS mRNA expression, compared with Ringer-treated axotomized cells. These results show that the administration of exogenous NGF in vivo, to the proximal nerve stump of the transected sciatic nerve, results in an upregulation of TTX-R sodium current and of alpha-SNS mRNA levels in small DRG neurons. Retrogradely transported NGF thus appears to participate in the control of excitability in these cells via actions that include the regulation of sodium channel gene expression in vivo. PMID:9582237

Dib-Hajj, S D; Black, J A; Cummins, T R; Kenney, A M; Kocsis, J D; Waxman, S G

1998-05-01

94

In Vivo Regulation of Brain-Derived Neurotrophic Factor in Dorsal Root Ganglia Is Mediated by Nerve Growth Factor-Triggered Akt Activation during Cystitis  

PubMed Central

The role of brain-derived neurotrophic factor (BDNF) in sensory hypersensitivity has been suggested; however the molecular mechanisms and signal transduction that regulate BDNF expression in primary afferent neurons during visceral inflammation are not clear. Here we used a rat model of cystitis and found that the mRNA and protein levels of BDNF were increased in the L6 dorsal root ganglia (DRG) in response to bladder inflammation. BDNF up-regulation in the L6 DRG was triggered by endogenous nerve growth factor (NGF) because neutralization of NGF with a specific NGF antibody reduced BDNF levels during cystitis. The neutralizing NGF antibody also subsequently reduced cystitis-induced up-regulation of the serine/threonine kinase Akt activity in L6 DRG. To examine whether the NGF-induced Akt activation led to BDNF up-regulation in DRG in cystitis, we found that in cystitis the phospho-Akt immunoreactivity was co-localized with BDNF in L6 DRG, and prevention of the endogenous Akt activity in the L6 DRG by inhibition of phosphoinositide 3-kinase (PI3K) with a potent inhibitor LY294002 reversed cystitis-induced BDNF up-regulation. Further study showed that application of NGF to the nerve terminals of the ganglion-nerve two-compartmented preparation enhanced BDNF expression in the DRG neuronal soma; which was reduced by pre-treatment of the ganglia with the PI3K inhibitor LY294002 and wortmannin. These in vivo and in vitro experiments indicated that NGF played an important role in the activation of Akt and subsequent up-regulation of BDNF in the sensory neurons in visceral inflammation such as cystitis.

Qiao, Li-Ya; Yu, Sharon J.; Kay, Jarren C.; Xia, Chun-Mei

2013-01-01

95

Laser-Guided Cervical Selective Nerve Root Block with the Dyna-CT: Initial Experience of Three-Dimensional Puncture Planning with an Ex-Vivo Model  

PubMed Central

Background Cervical selective nerve root block (CSNRB) is a well-established, minimally invasive procedure to treat radicular cervical pain. However, the procedure is technically challenging and might lead to major complications. The objective of this study was to evaluate the feasibility of a three-dimensional puncture planning and two-dimensional laser-guidance system for CSNRB in an ex-vivo model. Methods Dyna-CT of the cervical spine of an ex-vivo lamb model was performed with the Artis Zee® Ceiling (Siemens Medical Solutions, Erlangen, Germany) to acquire multiplanar reconstruction images. 15 cervical nerve root punctures were planned and conducted with the syngo iGuide® laser-guidance system. Needle tip location and contrast dye distribution were analyzed by two independent investigators. Procedural, planning, and fluoroscopic time, tract length, and dose area product (DAP) were acquired for each puncture. Results All 15 punctures were rated as successful with 12 punctures on the first attempt. Total procedural time was approximately 5 minutes. Mean planning time for the puncture was 2.03 (±0.39) min. Mean puncture time was 2.16 (±0.32) min, while mean fluoroscopy time was 0.17 (±0.06) min. Mean tract length was 2.68 (±0.23) cm. Mean total DAP was 397.45 (±15.63) µGy m2. Conclusion CSNRB performed with Dyna-CT and the tested laser guidance system is feasible. 3D pre-puncture planning is easy and fast and the laser-guiding system ensures very accurate and intuitive puncture control.

Al-Zghloul, Mansour; Groden, Christoph; Kerl, Hans U.

2013-01-01

96

Extracellular Nm23H1 stimulates neurite outgrowth from dorsal root ganglia neurons in vitro independently of nerve growth factor supplementation or its nucleoside diphosphate kinase activity  

SciTech Connect

Research highlights: {yields} Extracellular Nm23H1 stimulates nerve growth. {yields} Extracellular Nm23H1 provides pathfinding cues to growth cones. {yields} The neurotrophic activity of Nm23H1 is independent of NDP kinase activity. {yields} The neurotrophic activity of Nm23H1 is independent of NGF. -- Abstract: The nucleoside diphosphate (NDP) kinase, Nm23H1, is a highly expressed during neuronal development, whilst induced over-expression in neuronal cells results in increased neurite outgrowth. Extracellular Nm23H1 affects the survival, proliferation and differentiation of non-neuronal cells. Therefore, this study has examined whether extracellular Nm23H1 regulates nerve growth. We have immobilised recombinant Nm23H1 proteins to defined locations of culture plates, which were then seeded with explants of embryonic chick dorsal root ganglia (DRG) or dissociated adult rat DRG neurons. The substratum-bound extracellular Nm23H1 was stimulatory for neurite outgrowth from chick DRG explants in a concentration-dependent manner. On high concentrations of Nm23H1, chick DRG neurite outgrowth was extensive and effectively limited to the location of the Nm23H1, i.e. neuronal growth cones turned away from adjacent collagen-coated substrata. Nm23H1-coated substrata also significantly enhanced rat DRG neuronal cell adhesion and neurite outgrowth in comparison to collagen-coated substrata. These effects were independent of NGF supplementation. Recombinant Nm23H1 (H118F), which does not possess NDP kinase activity, exhibited the same activity as the wild-type protein. Hence, a novel neuro-stimulatory activity for extracellular Nm23H1 has been identified in vitro, which may function in developing neuronal systems.

Wright, K.T. [Keele University at the RJAH Orthopaedic Hospital, Oswestry, Shropshire (United Kingdom)] [Keele University at the RJAH Orthopaedic Hospital, Oswestry, Shropshire (United Kingdom); Seabright, R.; Logan, A. [Neuropharmacology and Neurobiology, School of Clinical and Experimental Medicine, Birmingham University, Birmingham (United Kingdom)] [Neuropharmacology and Neurobiology, School of Clinical and Experimental Medicine, Birmingham University, Birmingham (United Kingdom); Lilly, A.J.; Khanim, F.; Bunce, C.M. [Biosciences, Birmingham University, Birmingham (United Kingdom)] [Biosciences, Birmingham University, Birmingham (United Kingdom); Johnson, W.E.B., E-mail: w.e.johnson@aston.ac.uk [Life and Health Sciences, Aston University, Birmingham (United Kingdom)] [Life and Health Sciences, Aston University, Birmingham (United Kingdom)

2010-07-16

97

Caspase-2 Is Upregulated after Sciatic Nerve Transection and Its Inhibition Protects Dorsal Root Ganglion Neurons from Apoptosis after Serum Withdrawal  

PubMed Central

Sciatic nerve (SN) transection-induced apoptosis of dorsal root ganglion neurons (DRGN) is one factor determining the efficacy of peripheral axonal regeneration and the return of sensation. Here, we tested the hypothesis that caspase-2 (CASP2) orchestrates apoptosis of axotomised DRGN both in vivo and in vitro by disrupting the local neurotrophic supply to DRGN. We observed significantly elevated levels of cleaved CASP2 (C-CASP2), compared to cleaved caspase-3 (C-CASP3), within TUNEL+DRGN and DRG glia (satellite and Schwann cells) after SN transection. A serum withdrawal cell culture model, which induced 40% apoptotic death in DRGN and 60% in glia, was used to model DRGN loss after neurotrophic factor withdrawal. Elevated C-CASP2 and TUNEL were observed in both DRGN and DRG glia, with C-CASP2 localisation shifting from the cytosol to the nucleus, a required step for induction of direct CASP2-mediated apoptosis. Furthermore, siRNA-mediated downregulation of CASP2 protected 50% of DRGN from apoptosis after serum withdrawal, while downregulation of CASP3 had no effect on DRGN or DRG glia survival. We conclude that CASP2 orchestrates the death of SN-axotomised DRGN directly and also indirectly through loss of DRG glia and their local neurotrophic factor support. Accordingly, inhibiting CASP2 expression is a potential therapy for improving both the SN regeneration response and peripheral sensory recovery.

Vigneswara, Vasanthy; Berry, Martin

2013-01-01

98

p38 Mitogen-Activated Protein Kinase Is Activated after a Spinal Nerve Ligation in Spinal Cord Microglia and Dorsal Root Ganglion Neurons and Contributes to the Generation of Neuropathic Pain  

Microsoft Academic Search

The possible involvement of p38 mitogen-activated protein kinase activation in spinal cord and dorsal root ganglion (DRG) cells in the development of peripheral neuropathic pain has been explored. Ligation of the L5 spinal nerve (SNL) on one side in adult rats produces an early onset and long-lasting mechanical allodynia. This lesion results in activation of p38 in the L5 segment

Shan-Xue Jin; Zhi-Ye Zhuang; Clifford J. Woolf; Ru-Rong Ji

2003-01-01

99

Profiling of Dynamically Changed Gene Expression in Dorsal Root Ganglia Post Peripheral Nerve injury and A Critical Role of Injury-Induced Glial Fibrillary Acetic Protein in Maintenance of Pain Behaviors  

PubMed Central

To explore cellular changes in sensory neurons after nerve injury and identify potential target genes contributing to different stages of neuropathic pain development, we used Affymetrix oligo arrays to profile gene expression patterns in L5/6 dorsal root ganglia (DRG) from the neuropathic pain model of left L5/6 spinal nerve ligation at different stages of neuropathic pain development. Our data indicated that nerve injury induced changes in expression of genes with similar biological functions in a temporal specific manner that correlates with particular stages of neuropathic pain development, indicating dynamic neuroplasticity in the DRG in response to peripheral nerve injury and during neuropathic pain development. Data from post-array validation indicated that there was a temporal correlation between injury-induced expression of the glial fibrillary acidic protein (GFAP), a marker for activated astrocytes, and neuropathic pain development. Spinal nerve ligation injury in GFAP knockout mice resulted in neuropathic pain states with similar onset, but a shortened duration compared with that in age, and gender-matched wild-type littermates. Intrathecal GFAP antisense oligonucleotide treatment in injured rats with neuropathic pain states reversed injury-induced behavioral hypersensitivity and GFAP upregulation in DRG and spinal cord. Together, these findings indicate that injury-induced GFAP upregulation not only serves as a marker for astrocyte activation, but it may play a critical, but yet identified, role in the maintenance of neuropathic pain states.

Kim, Doo-sik; Figueroa, Katherine W.; Li, Kang-Wu; Boroujerdi, Amin; Yolo, Tim; Luo, Z. David

2009-01-01

100

Pinched Nerve  

MedlinePLUS

NINDS Pinched Nerve Information Page Table of Contents (click to jump to sections) What is Pinched Nerve? Is there any treatment? ... being done? Clinical Trials Organizations What is Pinched Nerve? The term "pinched nerve" is a colloquial term ...

101

The Division of the Sciatic Nerve in the Popliteal Fossa: Anatomical Implications for Popliteal Nerve Blockade  

Microsoft Academic Search

The sciatic nerve (SN) originates from the L4-S3 roots in the form of two nerve trunks: the tibial nerve (TN) and the common peroneal nerve (CPN). The TN and CPN are encompassed by a single epineural sheath and eventually separate (divide) in the popliteal fossa. This division of the SN occurs at a variable level above the knee and may

Jerry D. Vloka; Ernest April; Daniel M. Thys

2001-01-01

102

Effects of sciatic nerve transection on ultrastructure, NADPH-diaphorase reaction and serotonin-, tyrosine hydroxylase-, c-Fos-, glucose transporter 1- and 3-like immunoreactivities in frog dorsal root ganglion.  

PubMed

Frogs have been used as an alternative model to study pain mechanisms. Since we did not find any reports on the effects of sciatic nerve transection (SNT) on the ultrastructure and pattern of metabolic substances in frog dorsal root ganglion (DRG) cells, in the present study, 18 adult male frogs (Rana catesbeiana) were divided into three experimental groups: naive (frogs not subjected to surgical manipulation), sham (frogs in which all surgical procedures to expose the sciatic nerve were used except transection of the nerve), and SNT (frogs in which the sciatic nerve was exposed and transected). After 3 days, the bilateral DRG of the sciatic nerve was collected and used for transmission electron microscopy. Immunohistochemistry was used to detect reactivity for glucose transporter (Glut) types 1 and 3, tyrosine hydroxylase, serotonin and c-Fos, as well as nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-diaphorase). SNT induced more mitochondria with vacuolation in neurons, satellite glial cells (SGCs) with more cytoplasmic extensions emerging from cell bodies, as well as more ribosomes, rough endoplasmic reticulum, intermediate filaments and mitochondria. c-Fos immunoreactivity was found in neuronal nuclei. More neurons and SGCs surrounded by tyrosine hydroxylase-like immunoreactivity were found. No change occurred in serotonin- and Glut1- and Glut3-like immunoreactivity. NADPH-diaphorase occurred in more neurons and SGCs. No sign of SGC proliferation was observed. Since the changes of frog DRG in response to nerve injury are similar to those of mammals, frogs should be a valid experimental model for the study of the effects of SNT, a condition that still has many unanswered questions. PMID:23739744

Rigon, F; Rossato, D; Auler, V B; Dal Bosco, L; Faccioni-Heuser, M C; Partata, W A

2013-06-01

103

Bilateral Optic Nerve Meningioma  

Microsoft Academic Search

A case of bilateral optic nerve meningioma is reported. The onset of the clinical symptoms, at age 27, resembled unilateral optic neuritis with papilledema, leading to bilateral amaurosis with optic atrophy 4 years later. Skull X-ray revealed a ‘blistering’ type of bone reaction. In the carotid angiogram, the ophthalmic artery appeared quite enlarged and displaced. The CT scan showed a

H. Liaño; C. Garcia-Alix; M. Lousa; M. Marquez; L. Nombela; J. de Miguel

1982-01-01

104

[Radial nerve compression].  

PubMed

A new compression syndrome of the deep branch of the radial nerve is described, in which a sudden anterior displacement of a part of this nerve under maximal tension is followed by an axonotmesis. This happens in an area in which the deep branch of the radial nerve crossed some narrow structures which are unyielding and have more compression strength (tense cords of connective tissue Fig. 3). The operative finding of a torsion of the injured fascicles justifies the correctness of the immediate operative revision; otherwise the nerve regeneration would be impaired by the torted empty endoneural tubes. This description is a further constribution not observed before to the compression syndromes of the radial nerve, since in 1970 the author was able to give an explanation for the pathogenesis of compression palsies of the radial nerve, unclear up to that time but observed after forceful muscle contractions again and again since the beginning of this century. This observation gives the evidence that the occurrence of a peripheral compression lesion of nerves is not bound absolutely on the existence of a "physiological narrowness" (fibrous or osteofibrous tunnel etc.). This is also true for the median nerve. PMID:992486

Wilhelm, A

1976-01-01

105

steve bAccumulation of nerve growth factor and its receptors in the uterus and dorsal root ganglia in a mouse model of adenomyosis  

PubMed Central

Background Adenomyosis is a common gynecological disease, which is accompanied by a series of immunological and neuroendocrinological changes. Nerve growth factor (NGF) plays a critical role in producing pain, neural plasticity, immunocyte aggregation and release of inflammatory factors. This study aimed to investigate the expression of NGF and its two receptors in uteri and dorsal root ganglia (DRG) in an adenomyosis mouse model, as well as their relationship with the severity of adenomyosis. Methods Forty newborn ICR mice were randomly divided into the adenomyosis model group and control group (n = 20 in each group). Mice in the adenomyosis model group were orally dosed with 2.7 ?mol/kg tamoxifen on days 2-5 after birth. Experiments were conducted to identify the expression of NGF- beta and its receptors, tyrosine kinase receptor (trkA) and p75 neurotrophin receptor (p75NTR), in the uterus and DRG in four age groups (90+/-5 d, 140+/-5 d, 190+/-5 d and 240+/-5 d; n = 5 mice in each group) by western bolt, immunochemistry and real time reverse transcription-polymerase chain reaction. Results Adenomyosis, which became more serious as age increased, was successfully induced in dosed ICR mice. NGF-beta, trkA and p75NTR protein levels in the uterus and trkA mRNA levels in DRG were higher in the older aged adenomyosis model group than those in controls (190+/-5 d and 240+/-5 d groups, P < 0.05). The expression of NGF-beta and its receptors in the uterus increased gradually as age increased for adenomyosis mice (190+/-5 d and 240+/-5 d, P < 0.05, compared with 90+/-5 d) but it showed little change in control mice. The mRNA level of trkA in DRG also increased as age increased in the adenomyosis model group (190+/-5 d and 240+/-5 d, P < 0.05, compared with 90+/-5 d) but was unchanged in controls. The mRNA level of p75NTR in DRG was not different between the adenomyosis and control groups and was stable from young to old mice. Conclusions NGF- beta can be used as an indicator for the severity of adenomyosis. The gradually increasing level of NGF- beta and its receptors while the disease becomes more severe suggests an effect of NGF- beta on pathogenic mechanisms of adenomyosis.

2011-01-01

106

Magnetic stimulation of the pudendal nerve  

Microsoft Academic Search

Electroneurography of the pudendal nerve is extremely important in the diagnosis of neurogenic fecal incontinence and a pudendal canal syndrome. PURPOSE: The aim of this study was to determine pudendal nerve motor latency of the overall distance by stimulation of nerve root S3 by discharging a magnetic coil. METHODS: This can be achieved by positioning an earth electrode between the

Wolfgang H. Jost; Klaus Schimrigk

1994-01-01

107

Dynamic response to peripheral nerve injury detected by in situ hybridization of IL-6 and its receptor mRNAs in the dorsal root ganglia is not strictly correlated with signs of neuropathic pain  

PubMed Central

Background IL-6 is a typical injury-induced mediator. Together with its receptors, IL-6 contributes to both induction and maintenance of neuropathic pain deriving from changes in activity of primary sensory neurons in dorsal root ganglia (DRG). We used in situ hybridization to provide evidence of IL-6 and IL-6 receptors (IL-6R and gp130) synthesis in DRG along the neuraxis after unilateral chronic constriction injury (CCI) of the sciatic nerve as an experimental model of neuropathic pain. Results All rats operated upon to create unilateral CCI displayed mechanical allodynia and thermal hyperalgesia in ipsilateral hind paws. Contralateral hind paws and forepaws of both sides exhibited only temporal and nonsignificant changes of sensitivity. Very low levels of IL-6 and IL-6R mRNAs were detected in naïve DRG. IL-6 mRNA was bilaterally increased not only in DRG neurons but also in satellite glial cells (SGC) activated by unilateral CCI. In addition to IL-6 mRNA, substantial increase of IL-6R mRNA expression occurred in DRG neurons and SGC following CCI, while the level of gp130 mRNA remained similar to that of DRG from naïve rats. Conclusions Here we evidence for the first time increased synthesis of IL-6 and IL-6R in remote cervical DRG nonassociated with the nerve injury. Our results suggest that unilateral CCI of the sciatic nerve induced not only bilateral elevation of IL-6 and IL-6R mRNAs in L4–L5 DRG but also their propagation along the neuraxis to remote cervical DRG as a general neuroinflammatory reaction of the nervous system to local nerve injury without correlation with signs of neuropathic pain. Possible functional involvement of IL-6 signaling is discussed.

2013-01-01

108

Displaced Supersymmetry  

NASA Astrophysics Data System (ADS)

The apparent absence of light superpartners at the LHC strongly constrains the viability of the MSSM as a solution to the hierarchy problem. These constraints can be significantly alleviated by R-parity violation (RPV). Bilinear R-parity violation, with the single operator LH u , does not require any special flavor structure and can be naturally embedded in a GUT while avoiding constraints from proton decay (unlike baryon-number-violating RPV). The LSP in this scenario can be naturally long-lived, giving rise to displaced vertices. Many collider searches, particularly those selecting b-jets or leptons, are insensitive to events with such detector-scale displaced decays owing to cuts on track quality and impact parameter. We demonstrate that for decay lengths in the window ˜1-103 mm, constraints on superpartner masses can be as low as ˜450 GeV for squarks and ˜40 GeV for LSPs. In some parts of parameter space light LSPs can dominate the Higgs decay width, hiding the Higgs from existing searches. This framework motivates collider searches for detector-scale displaced vertices. LHCb may be ideally suited to trigger on such events, while ATLAS and CMS may need to trigger on missing energy or multijet signatures.

Graham, Peter W.; Kaplan, David E.; Rajendran, Surjeet; Saraswat, Prashant

2012-07-01

109

Anatomical variation of sciatic nerve division in the popliteal fossa and its implication in popliteal nerve blockade  

Microsoft Academic Search

The sciatic nerve (SN) originates from the L4-S3 roots in the form of two nerve trunks: the tibial nerve (TN) and the common peroneal nerve (CPN). The TN and CPN are encompassed by a single epineural sheath and eventually sepa- rate (divide) in the popliteal fossa. This division of the SN occurs at a variable level above the knee and

Folia Morphol; H. A. M. Saleh; M. M. O. El-fark; G. A. Abdel-Hamid

110

Expression of c-Fos and c-Jun in adjacent cervical spinal cord segments following C7 nerve root rhizotomy in rats: Indication of a neural pathway between adjacent cervical spinal cord segments  

PubMed Central

Cervical radiculopathy is a common disease in clinical practice. However, the symptoms are not confined to the affected spinal cord segment indicated by magnetic resonance imaging (MRI) findings. In the present study, we measured c-Fos and c-Jun expression in ipsilateral and adjacent cervical spinal cord segments following C7 nerve root rhizotomy, to determine whether there is a neural pathway between adjacent cervical spinal cord segments. Forty-eight adult male Wistar rats were randomly divided into two groups: the C7 rhizotomy group (rhizotomy group, n=24) and the sham-operated group (sham group, n=24). The right C7 nerve root was completely cut off in the rhizotomy group, while it was exposed but not cut in the sham group. The expression of c-Fos and c-Jun in cervical spinal cord segments was detected by immunohistochemistry at 2 and 4 h after surgery. We observed that the number of c-Fos- and c-Jun-positive neurons in ipsilateral C5–7 segments were significantly increased at 2 and 4 h after C7 nerve root rhizotomy (P<0.05 vs. the sham group). The location of c-Fosand c-Jun-positive neurons in C5–7 gray matter was similar in the rhizotomy and sham groups, which was mainly in lamina IX of the anterior horn and laminae I–II of the dorsal horn of the spinal cord. However, the number of c-Fos- and c-Jun-positive neurons in the C5–7 gray matter was significantly reduced at 4 h after surgery compared with the number 2 h after surgery. The location of c-Fos- and c-Jun-positive neurons at 4 h was similar with that at 2 h. Therefore, there may be a neural pathway between ipsilateral adjacent cervical spinal cord segments. This may be one possible explanation as to why the radicular symptoms of cervical radiculopathy are not confined to the affected spinal cord segment shown by MRI.

LI, HUI; LI, QING; XIE, KELIANG; FENG, SHIQING; WANG, PEI; MA, XINLONG

2013-01-01

111

Cranial Nerves IX, X, XI, and XII  

PubMed Central

This article concludes the series on cranial nerves, with review of the final four (IX–XII). To summarize briefly, the most important and common syndrome caused by a disorder of the glossopharyngeal nerve (craniel nerve IX) is glossopharyngeal neuralgia. Also, swallowing function occasionally is compromised in a rare but disabling form of tardive dyskinesia called tardive dystonia, because the upper motor portion of the glossopharyngel nerve projects to the basal ganglia and can be affected by lesions in the basal ganglia. Vagus nerve funtion (craniel nerve X) can be compromised in schizophrenia, bulimia, obesity, and major depression. A cervical lesion to the nerve roots of the spinal accessory nerve (craniel nerve XI) can cause a cervical dystonia, which sometimes is misdiagnosed as a dyskinesia related to neuroleptic use. Finally, unilateral hypoglossal (craniel nerve XII) nerve palsy is one of the most common mononeuropathies caused by brain metastases. Supranuclear lesions of cranial nerve XII are involved in pseudobulbar palsy and ALS, and lower motor neuron lesions of cranial nerve XII can also be present in bulbar palsy and in ALS patients who also have lower motor neuron involvement. This article reviews these and other syndromes related to cranial nerves IX through XII that might be seen by psychiatry.

Sanders, Richard D.

2010-01-01

112

Clarifying the nomenclature of intervertebral disc degeneration and displacement: from bench to bedside  

PubMed Central

As a significant determinant of low back pain, intervertebral disc degeneration (IDD) has attracted more and more attention of both investigators and physicians. Disc herniation, termed as intervertebral disc displacement, is amongst the most prevalent spinal diseases closely linked with IDD. Due to the same origins and similar pathophysiology, the ambiguity regarding the similarity and difference of IDD and intervertebral disc displacement thus remains. The aim of this study was to clarify the nomenclature of IDD and disc herniation in terms of molecular etiology, pathophysiology, nature history and clinical outcomes. Collectively, IDD is a type of multifaceted, progressive spinal disease with or without clinical symptoms as back pain, characterized by extracellular matrix and the integrity of NP and AF lost, fissures formation. Disc herniation (termed as intervertebral disc displacement) is a type of spinal disease based on IDD or not, with local pain and/or sciatica due to mechanical compression and autoimmune cascades upon the corresponding nerve roots. Clarifying the nomenclature of intervertebral disc degeneration and displacement has important implications both for investigators and for physicians.

Wang, Hai-Qiang; Samartzis, Dino

2014-01-01

113

Nerve repair, grafting, and nerve transfers.  

PubMed

Advances in the field of peripheral nerve surgery have increased our understanding of the complex cellular and molecular events involved in nerve injury and repair. Application of these important discoveries has led to important developments in the techniques of nerve repair, nerve grafting, nerve allografts, end-to-side repairs, and nerve-to-nerve transfers. As our understanding of this dynamic field increases, further improvement in functional outcomes after nerve injury and repair can be expected. PMID:12737353

Dvali, Linda; Mackinnon, Susan

2003-04-01

114

Common peroneal nerve dysfunction  

MedlinePLUS

Neuropathy - common peroneal nerve; Peroneal nerve injury; Peroneal nerve palsy ... The peroneal nerve is a branch of the sciatic nerve, which supplies movement and sensation to the lower leg, foot and ...

115

Optic Nerve Drusen  

MedlinePLUS

... Frequently Asked Questions Español Condiciones Chinese Conditions Optic Nerve Drusen En Español Read in Chinese What are optic nerve drusen? Optic nerve drusen are abnormal globular collections ...

116

Modeling root reinforcement using root-failure Weibull survival function  

NASA Astrophysics Data System (ADS)

Root networks contribute to slope stability through complicated interactions that include mechanical compression and tension. Due to the spatial heterogeneity of root distribution and the dynamic of root turnover, the quantification of root reinforcement on steep slope is challenging and consequently the calculation of slope stability as well. Although the considerable advances in root reinforcement modeling, some important aspect remain neglected. In this study we address in particular to the role of root strength variability on the mechanical behaviors of a root bundle. Many factors may contribute to the variability of root mechanical properties even considering a single class of diameter. This work presents a new approach for quantifying root reinforcement that considers the variability of mechanical properties of each root diameter class. Using the data of laboratory tensile tests and field pullout tests, we calibrate the parameters of the Weibull survival function to implement the variability of root strength in a numerical model for the calculation of root reinforcement (RBMw). The results show that, for both laboratory and field datasets, the parameters of the Weibull distribution may be considered constant with the exponent equal to 2 and the normalized failure displacement equal to 1. Moreover, the results show that the variability of root strength in each root diameter class has a major influence on the behavior of a root bundle with important implications when considering different approaches in slope stability calculation. Sensitivity analysis shows that the calibration of the tensile force and the elasticity of the roots are the most important equations, as well as the root distribution. The new model allows the characterization of root reinforcement in terms of maximum pullout force, stiffness, and energy. Moreover, it simplifies the implementation of root reinforcement in slope stability models. The realistic quantification of root reinforcement for tensile, shear and compression behavior allows the consideration of the stabilization effects of root networks on steep slopes and the influence that this has on the triggering of shallow landslides.

Schwarz, M.; Giadrossich, F.; Cohen, D.

2013-03-01

117

A precision mechanical nerve stimulator  

NASA Technical Reports Server (NTRS)

An electromechanical device, used to apply and monitor stimulating pulses to a mammalian motor nerve, has been successfully developed at NASA Langley Research Center. Two existing force transducers, a flight skin friction balance and a miniature skin friction balance which were designed for making aerodynamic drag measurements, were modified and incorporated to form this precision instrument. The nerve stimulator is a type one servomechanism capable of applying and monitoring stimulating pulses of 0 to 10 grams with a precision of better than +/- 0.05 grams. Additionally, the device can be independently used to apply stimulating pulses by displacing the nerve from 0 to 0.25 mm with a precision of better than +/- 0.001 mm while measuring the level of the load applied.

Tcheng, Ping; Supplee, Frank H., Jr.; Prass, Richard L.

1988-01-01

118

Soil-root mechanical interactions within bundles of roots  

NASA Astrophysics Data System (ADS)

Root-soil mechanical interactions play an important role in strength and force redistribution in rooted soil. Recent advances in root reinforcement modeling implement detailed representation of root geometry and mechanical properties as well as root-soil mechanical interactions. Nevertheless, root-soil mechanical interactions are often considered at the single root scale ignoring interactions between neighboring roots and root bundles known to play important role in similar applications such as engineered composite material reinforcement. The objective was to quantify mechanical interactions among neighboring roots or roots network using pullout laboratory experiments and modeling. We focus on the on effects of such interactions on global pull out force of a bundle of roots via better understanding of transmission of radial stresses to soil matrix due to the friction at the interface soil-root. Additionally, we wish to predict how cumulative friction changes along a single root axis with and without branching points during the slipping out. Analytical models of fiber reinforced materials show the magnitude of bonded friction depends on three key parameters: bond modulus, maximal bond strength and difference between the Young moduli of fiber and Young moduli of matrix. Debonded friction is calculated assuming failure follows Coulomb failure that includes apparent cohesion, effective normal stress and residual root soil friction angle. We used a pullout device to measure displacement and force of individual roots and for the bundle of roots. Additionally, we monitored and detected activation of root-soil friction by six acoustic emission sensors placed on waveguide in contact with the soil matrix. Results from experiments with parallel and crossing roots demonstrated the importance of considering factors such as distance of root axis, branching points, crossing of roots and roots diameter for the behavior of bundle of roots and inclined roots during pullout. Acoustic emission measurements provided interesting insights into progressive activation of root-soil friction. These results enhance understanding of root reinforcement mechanism and enable more realistic implementation of root reinforcement modeling for stability calculation of vegetated slopes.

Giadrossich, Filippo; Schwarz, Massimiliano; Preti, Federico; Or, Dani

2010-05-01

119

Peripheral nerve regeneration through optic nerve grafts  

Microsoft Academic Search

Grafts of optic nerve were placed end-toend with the proximal stumps of severed common peroneal nerves in inbred mice. It was found that fraying the proximal end of adult optic nerve grafts to disrupt the glia limitans increased their chances of being penetrated by regenerating peripheral nerve fibres. Suturing grafts to the proximal stump also enhanced their penetration by axons.

P. N. Anderson; P. Woodham; M. Turmaine

1989-01-01

120

Pure peroneal intraneural ganglion cyst ascending along the sciatic nerve.  

PubMed

Peroneal nerve entrapment is most commonly seen in the popliteal fossa. It is rarely caused by a ganglion. Intraneural ganglia, although uncommon and seldom cause serious complications, are well recognized and most commonly affect the common peroneal (lateral popliteal) nerve. Ganglionic cysts developing in the sheath of a peripheral nerve or joint capsule may cause compression neuropathy. The differential diagnosis should involve L5 root lesions, posttraumatic intraneural hemorrhage, nerve compression near the tendinous arch located at the fibular insertion of the peroneal longus muscle and nerve-sheath tumors. We present a unique case of a pure intraneural ganglion of the common peroneal nerve ascending along the sciatic nerve. This case underscores the importance of consideration of an intraneural ganglion cyst with sciatic nerve involvement. PMID:21534214

Tehli, Ozkan; Celikmez, Ramazan Cengiz; Birgili, Baris; Solmaz, Ilker; Celik, Ertugrul

2011-01-01

121

Rehabilitation of the trigeminal nerve  

PubMed Central

When it comes to restoring impaired neural function by means of surgical reconstruction, sensory nerves have always been in the role of the neglected child when compared with motor nerves. Especially in the head and neck area, with its either sensory, motor or mixed cranial nerves, an impaired sensory function can cause severe medical conditions. When performing surgery in the head and neck area, sustaining neural function must not only be highest priority for motor but also for sensory nerves. In cases with obvious neural damage to sensory nerves, an immediate neural repair, if necessary with neural interposition grafts, is desirable. Also in cases with traumatic trigeminal damage, an immediate neural repair ought to be considered, especially since reconstructive measures at a later time mostly require for interposition grafts. In terms of the trigeminal neuralgia, commonly thought to arise from neurovascular brainstem compression, a pharmaceutical treatment is considered as the state of the art in terms of conservative therapy. A neurovascular decompression of the trigeminal root can be an alternative in some cases when surgical treatment is sought after. Besides the above mentioned therapeutic options, alternative treatments are available.

Iro, Heinrich; Bumm, Klaus; Waldfahrer, Frank

2005-01-01

122

Precision displacement reference system  

DOEpatents

A precision displacement reference system is described, which enables real time accountability over the applied displacement feedback system to precision machine tools, positioning mechanisms, motion devices, and related operations. As independent measurements of tool location is taken by a displacement feedback system, a rotating reference disk compares feedback counts with performed motion. These measurements are compared to characterize and analyze real time mechanical and control performance during operation.

Bieg, Lothar F. (Albuquerque, NM); Dubois, Robert R. (Albuquerque, NM); Strother, Jerry D. (Edgewood, NM)

2000-02-22

123

XY displacement device  

Microsoft Academic Search

An XY-displacement device (1) with a four-fold symmetry comprises a reference frame (10); an object mount (20) for holding an object (22) to be displaced; an X-manipulator (100) coupled between the reference frame (10) and the object mount (20), which provides a rigid coupling between the object mount (20) and a piezoelectric X-actuator (140), allows a Y-displacement of the object

W. C. Heerens; C. D. Laham; A. E. Holman

1997-01-01

124

Root systems  

NSDL National Science Digital Library

One purpose that roots serve is that of anchoring the plant in the ground. Roots also take up water and nutrients for the plant. Plants all have different root system types to fit their individual needs and locations.

N/A N/A (U.S. Government;)

2004-10-30

125

Re-Innervation of the Bladder through End-to-Side Neurorrhaphy of Autonomic Nerve and Somatic Nerve in Rats  

PubMed Central

Abstract End-to-side neurorrhaphy is widely used in the peripheral nervous system for nerve repair; however, the application of this technique has been limited to somatic nerves. The feasibility of nerve regeneration through end-to-side neurorrhaphy between autonomic and somatic nerves with different characteristics in the peripheral nervous system is still undetermined. In this study, rats were divided into three groups for different treatments (n=10 per group). In the end-to-side neurorrhaphy group, left L6 and S1 were transected in the dura, and the distal stump of L6 ventral root was sutured to the lateral face of L4 ventral root through end-to-side coaptation. In the no repair group, the rats did not undergo neurorrhaphy. In the control group, the left L6 dorsal root and S1 roots were transected, respectively, but the L6 ventral root was kept intact. After 16 weeks, the origin and mechanism of nerve regeneration was evaluated by retrograde double labeling technique as well as histological examination and intravesical pressure measurement. Retrograde double labeling indicated that the reconstructed reflex pathway was successfully established and the primary regeneration mechanism involved axon collateral sprouting. Morphological examination and intravesical pressure measurement indicated prominent nerve regeneration and successful re-innervation of the bladder in the neurorrhaphy group, compared with the “no repair” group (p<0.05). No significant changes were observed in the histology of the donor nerve and the bilateral extensor digitorum longus muscles in the neurorrhaphy group. Nerve regeneration may be achievable for nerve repair through end-to-side neurorrhaphy between autonomic and somatic nerves without apparent impairment of donor somatic nerve.

Gao, Wan-sheng; Dong, Chuan-jiang; Li, Shu-qiang; Kunwar, Kiran Jang

2012-01-01

126

Laparoscopic nerve-sparing transperitoneal approach for endometriosis infiltrating the pelvic wall and somatic nerves: anatomical considerations and surgical technique  

Microsoft Academic Search

Purpose  Endometriotic or fibrotic involvement of sacral plexus and pudendal and sciatic nerves may be quite frequently the endopelvic\\u000a cause of ano-genital and pelvic pain. Feasibility of a laparoscopic transperitoneal approach to the somatic nerves of the\\u000a pelvis was determined and showed by Possover et al. for diagnosis and treatment of ano-genital pain caused by pudendal and\\/or\\u000a sacral nerve roots lesions

Marcello Ceccaroni; Roberto Clarizia; Carlo Alboni; Giacomo Ruffo; Francesco Bruni; Giovanni Roviglione; Marco Scioscia; Inge Peters; Giuseppe De Placido; Luca Minelli

2010-01-01

127

Optic Nerve Imaging  

MedlinePLUS

Optic Nerve Imaging email Send this article to a friend by filling out the fields below: Your name: Your ... measurements of nerve fiber damage (or loss). The Nerve Fiber Analyzer (GDx) uses laser light to measure ...

128

Femoral nerve damage (image)  

MedlinePLUS

The femoral nerve is located in the leg and supplies the muscles that assist help straighten the leg. It supplies sensation ... leg. One risk of damage to the femoral nerve is pelvic fracture. Symptoms of femoral nerve damage ...

129

Ulnar nerve damage (image)  

MedlinePLUS

The ulnar nerve originates from the brachial plexus and travels down arm. The nerve is commonly injured at the elbow because of elbow fracture or dislocation. The ulnar nerve is near the surface of the body where ...

130

Nerve conduction velocity  

MedlinePLUS

Nerve conduction velocity (NCV) is a test to see how fast electrical signals move through a nerve. ... surface electrodes are placed on the skin over nerves at various locations. Each patch gives off a ...

131

Optic Nerve Pit  

MedlinePLUS

... Conditions Frequently Asked Questions Español Condiciones Chinese Conditions Optic Nerve Pit What is optic nerve pit? An optic nerve pit is a ... may be seen in both eyes. How is optic pit diagnosed? If the pit is not affecting ...

132

Compressed Facade Displacement Maps  

Microsoft Academic Search

We describe an approach to render massive urban models. To prevent a memory transfer bottleneck, we propose to render the models from a compressed representation directly. Our solution is based on rendering crude building outlines as polygons and generating details by ray-tracing displacement maps in the fragment shader. We demonstrate how to compress a displacement map so that a decompression

Saif Ali; Jieping Ye; Anshuman Razdan; Peter Wonka

2009-01-01

133

Root-soil mechanical interactions during pullout and failure of root bundles  

NASA Astrophysics Data System (ADS)

Roots play a major role in reinforcing and stabilizing steep hillslopes. Most studies in slope stability implement root reinforcement as an apparent cohesion by upscaling the behavior of static individual roots. Recent studies, however, have shown that much better predictions of slope stability can be made if the progressive failure of bundles of roots are considered. The characteristics of progressive failure depend on interactions between soil deformation and root bundle geometric and mechanical properties. We present a detailed model for the quantitative description of the mechanical behavior of a bundle of roots under strain-controlled mechanical forcing. The Root Bundle Model explicitly considers typical values of root-size spatial distribution (number and dimension of roots), geometric factors (diameter-length proportion, tortuosity, and branching characteristics), and mechanical characteristics (tensile strength and Young's modulus) and interactions under various soil conditions (soil type, confining pressure, and soil moisture). We provide systematic analyses of the roles of these factors on the mechanical response of the bundle and explore the relative importance of various parameters to the macroscopic root-soil mechanical response. We distinguish between increased strength imparted by small roots at small deformations and the resilience imparted by larger roots to the growth of large tensile cracks, showing that the maximal reinforcement of fine roots is reached within the first 5 cm of displacement whereas a root of 20 mm diameter may reach its maximal pullout force after 10 cm displacement. The model reproduces the gradual straining and ultimate residual failure behavior of root systems often observed in hillslopes, with progressive growth of tension cracks improving estimations of root reinforcement when considering the effects of root distribution and the variation of the pullout force as a function of displacement. These results enhance understanding of root reinforcement mechanisms and enable more realistic implementation of root reinforcement modeling for stability calculations of vegetated slopes and for guiding ongoing experimental efforts to gather critical root-soil mechanical information.

Schwarz, M.; Cohen, D.; Or, D.

2010-12-01

134

Nerve Impulses in Plants  

ERIC Educational Resources Information Center

Summarizes research done on the resting and action potential of nerve impulses, electrical excitation of nerve cells, electrical properties of Nitella, and temperature effects on action potential. (GS)

Blatt, F. J.

1974-01-01

135

Afferent fibres in cat ventral roots: electrophysiological and histological evidence.  

PubMed Central

Electrophysiological experiments using averaging techniques, as well as anatomical experiments using horseradish peroxidase staining, have provided further evidence of afferent axons in lumbosacral ventral roots of cats. Recording from dorsal root filaments in L7, S1 or S2, following stimulation of the companion ventral root close to the dura, often shows action potentials of slow conduction velocity belonging to the A delta or C group. Stimulation applied to the proximal part of the ventral root failed to evoke such responses. Recording from multiple sites along a centrally cut ventral root filament shows responses of two types: action potentials of long latency to peripheral nerve stimulation which are seen at all recording locations and which are not seen following dorsal root stimulation. These appear to be afferent fibres which enter the cord via the ventral root; action potentials which follow dorsal root stimulation and which are usually seen only at the most distal ventral root recording site. Some of these were also activated by stimulation of some skin or muscle nerves. At appropriate intervals collision of impulses from dorsal root or peripheral nerve can be demonstrated. Such axons appear to have a recurrent course in the ventral root. Section of the spinal nerve at points progressively closer to the dorsal root ganglion abolishes the dorsal to ventral root continuity of most recurrent type axons at 2 mm distal to the ganglion. Following application of horseradish peroxidase to crushed ends of distal stumps of cut dorsal roots, thin fibres marked by the enzyme are observed in the distal part of companion ventral roots. U-turns of axons have been observed in the distal part of ventral roots and in the spinal nerve near the pole of the ganglion. Images Plate 1

Azerad, J; Hunt, C C; Laporte, Y; Pollin, B; Thiesson, D

1986-01-01

136

Residential Displacement: An Update.  

National Technical Information Service (NTIS)

The report provides an assessment of the displacement phenomenon, based mainly on the results of HUD-sponsored research and technical assistance projects. A summary of these projects' results addresses the neighborhood revitalization process and displacem...

M. S. Davis G. Ferguson

1981-01-01

137

Advanced Triangulation Displacement Sensors  

NASA Technical Reports Server (NTRS)

Advanced optoelectronic triangulation displacement sensors undergoing development. Highly miniaturized, more stable, more accurate, and relatively easy to use. Incorporate wideband electronic circuits suitable for real-time monitoring and control of displacements. Measurements expected to be accurate to within nanometers. In principle, sensors mass-produced at relatively low unit cost. Potential applications numerous. Possible industrial application in measuring runout of rotating shaft or other moving part during fabrication in "zero-defect" manufacturing system, in which measured runout automatically corrected.

Poteet, Wade M.; Cauthen, Harold K.

1996-01-01

138

Internal displacement in Burma.  

PubMed

The internal displacement of populations in Burma is not a new phenomenon. Displacement is caused by numerous factors. Not all of it is due to outright violence, but much is a consequence of misguided social and economic development initiatives. Efforts to consolidate the state by assimilating populations in government-controlled areas by military authorities on the one hand, while brokering cease-fires with non-state actors on the other, has uprooted civilian populations throughout the country. Very few areas in which internally displaced persons (IDPs) are found are not facing social turmoil within a climate of impunity. Humanitarian access to IDP populations remains extremely problematic. While relatively little information has been collected, assistance has been focused on targeting accessible groups. International concern within Burma has couched the problems of displacement within general development modalities, while international attention along its borders has sought to contain displacement. With the exception of several recent initiatives, few approaches have gone beyond assistance and engaged in the prevention or protection of the displaced. PMID:11026156

Lanjouw, S; Mortimer, G; Bamforth, V

2000-09-01

139

Bilateral absence of musculocutaneous nerve with unusual branching pattern of lateral cord and median nerve of brachial plexus  

PubMed Central

A 43-year-old female cadaver showed a complete bilateral absence of the musculocutaneous nerve. The anterior compartment muscles of both arms were supplied by median nerve excepting the coracobrachialis which was innervated by a direct branch from the lateral cord of brachial plexus. The median nerve, after supplying the biceps and brachialis muscles, gave onto the lateral cutaneous nerve of the forearm. The median nerve also showed variation on the left side where it was formed by two lateral roots and one medial root. Variations of the brachial plexus are of great interest to anatomists, clinicians and surgeons, in that they may be incorporated in their day to day practice. Our present case may be noted for its clinical and surgical significance in the variations of brachial plexus which can be useful for diagnostic purposes.

Sankar, K. Devi

2012-01-01

140

Nerve injuries about the elbow in the athlete.  

PubMed

The athlete's elbow is a remarkable example of motion, strength, and durability. The stress placed on the elbow during sport, including the throwing motion, may lead to soft-tissue ligamentous and nerve injury. The thrower's elbow illustrates one example of possible nerve injury about the elbow in sport, related to chronic repetitive tensile and compressive stresses to the ulnar nerve associated with elbow flexion and valgus position. Besides the throwing athlete, nerve injury from high-energy direct-impact forces may also damage nerves around the elbow in contact sports. Detailed history and physical examination can often make the diagnosis of most upper extremity neuropathies. The clinician must be aware of the possibility of isolated or combined nerve injury as far proximal as the cervical nerve roots, through the brachial plexus, to the peripheral nerve terminal branches. Electrodiagnostic studies are occasionally beneficial for diagnosis with certain nerves. Nonoperative management is often successful in most elbow and upper extremity neuropathies. If conservative treatment fails, then surgical treatment should address all potentially offending structures. In the presence of medial laxity and concurrent ulnar neuritis, the medial ulnar collateral ligament warrants surgical treatment, in addition to transposition of the ulnar nerve. The morbidity of open surgical decompression of nerves in and around the elbow is potentially career threatening in the throwing athlete. This mandates an assessment of the adequacy of the nonsurgical treatment and a thorough preoperative discussion of the risks and benefits of surgery. PMID:25077754

Harris, Joshua D; Lintner, David M

2014-09-01

141

Water displacement mercury pump  

DOEpatents

A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

Nielsen, Marshall G. (Woodside, CA)

1985-01-01

142

Water displacement mercury pump  

DOEpatents

A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

Nielsen, M.G.

1984-04-20

143

Bragg optical displacement sensor  

NASA Astrophysics Data System (ADS)

A novel optical displacement sensor based on Bragg effect is described. A green light bema was used to excite a Rh6G dye solution in Shank type geometry. The beam was split up by a dielectric mirror and the two equal intensity vertically polarized light beams were folded by two mirrors to interfere in the dye cell. The lasing wavelength was found to be a precise function of the half angle between the beams. The vibrating body was attached to one of the folding mirror. In normal operation the lasing line wavelength was unchanged but during mirror vibration corresponding to this 1 degree was 87 micrometers . The sensor resolution was about 1.3 angstrom/micrometers . This ultrashell displacement sensor can be used to determine the frequency of vibration or simple displacements in ultraprecise applications.

Khan, Nasrullah

1999-11-01

144

Optical displacement sensor  

DOEpatents

An optical displacement sensor is disclosed which uses a vertical-cavity surface-emitting laser (VCSEL) coupled to an optical cavity formed by a moveable membrane and an output mirror of the VCSEL. This arrangement renders the lasing characteristics of the VCSEL sensitive to any movement of the membrane produced by sound, vibrations, pressure changes, acceleration, etc. Some embodiments of the optical displacement sensor can further include a light-reflective diffractive lens located on the membrane or adjacent to the VCSEL to control the amount of lasing light coupled back into the VCSEL. A photodetector detects a portion of the lasing light from the VCSEL to provide an electrical output signal for the optical displacement sensor which varies with the movement of the membrane.

Carr, Dustin W. (Albuquerque, NM)

2008-04-08

145

Internally displaced persons.  

PubMed

There were estimated to be over 20 million internally displaced persons (IDPs) at the end of 1999, a number that surpasses global estimates of refugees. Displacement exposes IDPs to new hazards and accrued vulnerability. These dynamics result in greater risk for the development of illness and death. Often, access of IDPs to health care and humanitarian assistance is excluded deliberately by conflicting parties. Furthermore, the arrival of IDPs into another community or region strains local health systems, and the host population ends up sharing the sufferings of the internally displaced. Health outcomes are dismaying. From a health perspective, the best option is to avoid human displacement. WHO contributes to the prevention of displacement by working for sustainable development. Placing health high on the political agenda helps maintain stability, and thereby, reduce the likelihood for displacement. Primary responsibility for assisting IDPs, irrespective of the cause, rests with the national government. However, where the government is unwilling or unable to provide the necessary aid, the international humanitarian community must step in, with WHO playing a major role in the health sector. There is consensus among the partners of the World Health Organization (WHO) that, in emergencies, the WHO must: 1) take the lead in rapid health assessment, epidemiological and nutritional surveillance, epidemic preparedness, essential drugs management, control of communicable diseases, and physical and psychosocial rehabilitation; and 2) provide guidelines and advice on nutritional requirements and rehabilitation, immunisation, medical relief items, and reproductive health. If the vital health needs of IDPs--security, food, water, shelter, sanitation and household items--are not satisfied, the provision of health services alone cannot save lives. Community participation is essential, and community participation implies bolstering the assets and capacities of the beneficiaries. PMID:11875794

Leus, X; Wallace, J; Loretti, A

2001-01-01

146

Thoracic splanchnic nerves: implications for splanchnic denervation  

PubMed Central

Splanchnic neurectomy is of value in the management of chronic abdominal pain. It is postulated that the inconsistent results of splanchnicectomies may be due to anatomical variations in the pattern of splanchnic nerves. The advent of minimally invasive and video-assisted surgery has rekindled interest in the frequency of variations of the splanchnic nerves. The aims of this study were to investigate the incidence, origin and pattern of the splanchnic nerves in order to establish a predictable pattern of splanchnic neural anatomy that may be of surgical relevance. Six adult and 14 fetal cadavers were dissected (n = 38). The origin of the splanchnic nerve was bilaterally asymmetrical in all cases. The greater splanchnic nerve (GSN) was always present, whereas the lesser splanchnic nerve (LSN) and least splanchnic nerve (lSN) were inconsistent (LSN, 35 of 38 sides (92%); LSN, 21 of 38 sides (55%). The splanchnic nerves were observed most frequently over the following ranges: GSN, T6–9: 28 of 38 sides (73%); LSN, when present, T10–11: (10 of 35 sides (29%); and lSN, T11–12: 3 of 21 sides (14%). The number of ganglionic roots of the GSN varied between 3 and 10 (widest T4–11; narrowest, T5–7). Intermediate splanchnic ganglia, when present, were observed only on the GSN main trunk with an incidence of 6 of 10 sides (60%) in the adult and 11 of 28 sides (39%) in the fetus. The higher incidence of the origin of GSN above T5 has clinical implications, given the widely discussed technique of undertaking splanchnicectomy from the T5 ganglion distally. This approach overlooks important nerve contributions and thereby may compromise clinical outcome. In the light of these variations, a reappraisal of current surgical techniques used in thoracoscopic splanchnicectomy is warranted.

NAIDOO, N.; PARTAB, P.; PATHER, N.; MOODLEY, J.; SINGH, B.; SATYAPAL, K. S.

2001-01-01

147

Root Hairs  

PubMed Central

Roots hairs are cylindrical extensions of root epidermal cells that are important for acquisition of nutrients, microbe interactions, and plant anchorage. The molecular mechanisms involved in the specification, differentiation, and physiology of root hairs in Arabidopsis are reviewed here. Root hair specification in Arabidopsis is determined by position-dependent signaling and molecular feedback loops causing differential accumulation of a WD-bHLH-Myb transcriptional complex. The initiation of root hairs is dependent on the RHD6 bHLH gene family and auxin to define the site of outgrowth. Root hair elongation relies on polarized cell expansion at the growing tip, which involves multiple integrated processes including cell secretion, endomembrane trafficking, cytoskeletal organization, and cell wall modifications. The study of root hair biology in Arabidopsis has provided a model cell type for insights into many aspects of plant development and cell biology.

Grierson, Claire; Nielsen, Erik; Ketelaarc, Tijs; Schiefelbein, John

2014-01-01

148

Needs of Displaced Homemakers.  

ERIC Educational Resources Information Center

As part of its five-year state plan for vocational education, the California State Department of Education and the Chancellor's Office of the California Community Colleges commissioned a study of the needs of displaced homemakers. (These women's needs were relevant to the state's plans for vocational education because the Education Amendments of…

Arnold, Carolyn; Marzone, Jean

149

Somatosensory evoked potentials to median nerve stimulation in meningomyelocele: what is occurring in the hindbrain and its connections during growth?  

Microsoft Academic Search

Twenty patients with meningomyelocele (MMC) and shunted hydrocephalus, ranging in age from 3 to 23 years old, underwent serial recording of short-latency somatosensory evoked potentials (SEPs) to median nerve stimulation, on the basis of which to assess the evolution of dysfunction in the brainstem and its connections (cervical spinal cord, cervical nerve roots, lower cranial nerves). Eighteen patients had Chiari

Toshihiko Nishimura; Koreaki Mori

1996-01-01

150

Regeneration of phasic synapses on a crayfish slow muscle following allotransplantation of a mixed phasic-tonic nerve  

Microsoft Academic Search

Separate phasic or tonic nerves allotransplanted to reinnervate a denervated slow superficial flexor muscle (SFM) in the abdomen of adult crayfish regenerate synaptic nerve terminals with phasic or tonic properties. To test competitive interactions between tonic and phasic axons, we allotransplanted the sixth abdominal ganglion with its third nerve root containing a mixture of phasic and tonic axons onto the

Rosalind Coulthard; C. K. Govind

2001-01-01

151

Nerve Injuries in Athletes.  

ERIC Educational Resources Information Center

Over a two-year period this study evaluated the condition of 65 athletes with nerve injuries. These injuries represent the spectrum of nerve injuries likely to be encountered in sports medicine clinics. (Author/MT)

Collins, Kathryn; And Others

1988-01-01

152

Radial nerve dysfunction (image)  

MedlinePLUS

The radial nerve travels down the arm and supplies movement to the triceps muscle at the back of the upper arm. ... the wrist and hand. The usual causes of nerve dysfunction are direct trauma, prolonged pressure on the ...

153

Diabetes and nerve damage  

MedlinePLUS

Nerve damage that occurs in people with diabetes is called diabetic neuropathy. This condition is a complicaiton ... In people with diabetes, the body's nerves can be damaged by ... level . This condition is more likely when blood sugar level ...

154

Electronic Nerve Agent Detector.  

National Technical Information Service (NTIS)

A personal field chemical warfare nerve agent detector has therein a transducer having two microchemical cantilever oscillators. One of the cantilever oscillators has deposited, as an end-mass, a chemically selective substance on the cantilever. The nerve...

E. S. Kolesar

1983-01-01

155

Engineering peripheral nerve repair.  

PubMed

Current approaches for treating peripheral nerve injury have resulted in promising, yet insufficient functional recovery compared to the clinical standard of care, autologous nerve grafts. In order to design a construct that can match the regenerative potential of the autograft, all facets of nerve tissue must be incorporated in a combinatorial therapy. Engineered biomaterial scaffolds in the future will have to promote enhanced regeneration and appropriate reinnervation by targeting the highly sensitive response of regenerating nerves to their surrounding microenvironment. PMID:23790730

Marquardt, Laura M; Sakiyama-Elbert, Shelly E

2013-10-01

156

Cranial Nerves Model  

NSDL National Science Digital Library

Lesson is designed to introduce students to cranial nerves through the use of an introductory lecture. Students will then create a three-dimensional model of the cranial nerves. An information sheet will accompany the model in order to help students learn crucial aspects of the cranial nerves.

Juliann Garza (University of Texas-Pan American Physician Assistant Studies)

2010-08-16

157

Laryngeal nerve damage  

MedlinePLUS

Laryngeal nerve damage is injury to one or both of the nerves that are attached to the voice box. ... Injury to the laryngeal nerves is uncommon. It it does occur, it can be from: A complication of neck or chest surgery (especially thyroid, lung, ...

158

Pullout tests of root analogs and natural root bundles in soil: Experiments and modeling  

NASA Astrophysics Data System (ADS)

Root-soil mechanical interactions are key to soil stability on steep hillslopes. Motivated by new advances and applications of the Root Bundle Model (RBM), we conducted a series of experiments in the laboratory and in the field to study the mechanical response of pulled roots. We systematically quantified the influence of different factors such as root geometry and configuration, soil type, and soil water content considering individual roots and root bundles. We developed a novel pullout apparatus for strain-controlled field and laboratory tests of up to 13 parallel roots measured individually and as a bundle. Results highlight the importance of root tortuosity and root branching points for prediction of individual root pullout behavior. Results also confirm the critical role of root diameter distribution for realistic prediction of global pullout behavior of a root bundle. Friction between root and soil matrix varied with soil type and water content and affected the force-displacement behavior. Friction in sand varied from 1 to 17 kPa, with low values obtained in wet sand at a confining pressure of 2 kPa and high values obtained in dry sand with 4.5 kPa confining pressure. In a silty soil matrix, friction ranged between 3 kPa under wet and low confining pressure (2 kPa) and 6 kPa in dry and higher confining pressure (4.5 kPa). Displacement at maximum pullout force increased with increasing root diameter and with tortuosity. Laboratory experiments were used to calibrate the RBM that was later validated using six field measurements with natural root bundles of Norway spruce (Picea abies L.). These tests demonstrate the progressive nature of root bundle failure under strain-controlled pullout force and provide new insights regarding force-displacement behavior of root reinforcement, highlighting the importance of considering displacement in slope stability models. Results show that the magnitude of maximum root pullout forces (1-5 kPa) are important for slope stability. The force-displacement relations characterized in this study are fundamental inputs for quantifying the resistive force redistribution on vegetated slopes and may provide explanation for abrupt loss of strength during landslide initiation and deformation.

Schwarz, M.; Cohen, D.; Or, D.

2011-06-01

159

Displacement and Velocity Ratios  

NSDL National Science Digital Library

This interactive presentation, created by James Bourassa and John Rosz for the Electromechanical Digital Library, discusses displacement and velocity ratios. Bourassa and Rosz begin by providing detailed definitions of both topics and then provide mathematical examples of each. Once this basic explanation is complete, the authors allow students to practice these theories in a set of self-correcting quiz questions. Bourassa and Rosz explain each using helpful interactive flash animations. These are not only useful in explanation, but they allow the student to more fully engage with the topic. Overall, this is a nice introduction to the physical and mathematical concepts of displacement and velocity ratios. This could be a valuable learning resource in everything from a physics to a technical education classroom.

Bourassa, James; Rosz, John

2011-04-05

160

Optical displacement measuring device  

Microsoft Academic Search

Theoretical considerations of a lightweight, frictionless, optical displacement measuring device (ODMD) are discussed. Experimental results show its resolution and accuracy to be better than 2.5 x 10 to the -8th m with a linear range of 7.5 x 10 to the -5th m, and less than 0.2% change of voltage signal in 600 hours; it has high cycling ability, no

G. F. Weissmann; H. L. Carter Jr.; R. R. Hart

1979-01-01

161

Different multiple regeneration capacities of motor and sensory axons in peripheral nerve.  

PubMed

After peripheral nerve injury, axons often project sprouts from the node of Ranvier proximal to the damage site. It is well known that one parent axon can sprout and maintain several regenerating axons. If enough endoneurial tubes in the distal stump are present for the regenerating axons to grow along, then the number of mature myelinated nerve fibers in the distal stump will be greater than the number in the proximal stump. "Multiple regeneration" is used to describe this phenomenon in the peripheral nerve. According to previous studies, a prominent nerve containing many axons can be repaired by the multiple regenerating axons sprouting from another nerve that contains fewer axons. Most peripheral nerves contain a mixture of myelinated motor and sensory axons as well as unmyelinated sensory and autonomic axons. In this study, a multiple regeneration animal model was developed by bridging the proximal common peroneal nerve with the distal common peroneal nerve and the tibial nerve. Differences in the multiple regeneration ratio of motor and sensory nerves were evaluated using histomorphometry one month after ablating the dorsal root ganglion (DRGs) and ventral roots, respectively. The results suggest that the motor nerves have a significantly larger multiple regeneration ratio than the sensory nerves at two different time points. PMID:22409279

Jianping, Peng; Xiaofeng, Yin; Yanhua, Wang; Zhenwei, Wang; Yuhui, Kou; Chungui, Xu; Peixun, Zhang; Baoguo, Jiang

2012-10-01

162

Paracrine Regulation of Pancreatic Cancer Cell Invasion by Peripheral Nerves  

PubMed Central

Background The ability of cancer to infiltrate along nerves is a common clinical observation in pancreas, head and neck, prostate, breast, and gastrointestinal carcinomas. For these tumors, nerves may provide a conduit for local cancer progression into the central nervous system. Although neural invasion is associated with poor outcome, the mechanism that triggers it is unknown. Methods We used an in vitro Matrigel dorsal root ganglion and pancreatic cancer cell coculture model to assess the dynamic interactions between nerves and cancer cell migration and the role of glial cell-derived neurotrophic factor (GDNF). An in vivo murine sciatic nerve model was used to study how nerve invasion affects sciatic nerve function. Results Nerves induced a polarized neurotrophic migration of cancer cells (PNMCs) along their axons, which was more efficient than in the absence of nerves (migration distance: mean?=?187.1 ?m, 95% confidence interval [CI]?=?148 to 226 ?m vs 14.4 ?m, 95% CI = 9.58 to 19.22 ?m, difference = 143 ?m; P < .001; n = 20). PNMC was induced by secretion of GDNF, via phosphorylation of the RET-Ras–mitogen-activated protein kinase pathway. Nerves from mice deficient in GDNF had reduced ability to attract cancer cells (nerve invasion index: wild type vs gdnf+/?, mean = 0.76, 95% CI = 0.75 to 0.77 vs 0.43, 95% CI = 0.42 to 0.44; P < .001; n = 60–66). Tumor specimens excised from patients with neuroinvasive pancreatic carcinoma had higher expression of the GDNF receptors RET and GRF?1 as compared with normal tissue. Finally, systemic therapy with pyrazolopyrimidine-1, a tyrosine kinase inhibitor targeting the RET pathway, suppressed nerve invasion toward the spinal cord and prevented paralysis in mice. Conclusion These data provide evidence for paracrine regulation of pancreatic cancer invasion by nerves, which may have important implications for potential therapy directed against nerve invasion by cancer.

Cavel, Oren; Kelly, Kaitlyn; Brader, Peter; Rein, Avigail; Gao, Sizhi P.; Carlson, Diane L.; Shah, Jatin P.; Fong, Yuman

2010-01-01

163

High-resolution ultrasonography for the diagnosis of brachial plexus root lesions.  

PubMed

The aim of this study was to investigate the feasibility of using high-resolution ultrasonography in the diagnosis of brachial plexus (BP) root lesions. A prospective study of ultrasonographic evaluation of BP nerve roots was performed in 37 patients with BP root lesions (29 with root injuries, 8 with tumors). The pre-operative ultrasonographic findings were compared with the surgical and pathohistological findings. All C5-7 roots were detected by ultrasonography in all patients, whereas 92% (68/74) of C8 and 51% (38/74) of T1 nerve roots were visualized. Among 29 patients with BP root avulsion, partial injuries or totally interrupted BP roots were detected in all patients. Cystic masses and neuromas were detected in 16 and 23 patients, respectively. In 8 patients with BP root tumors, 8 hypo-echoic masses were detected inside or partly outside of intervertebral foramina connecting to nerve roots. Surgical exploration revealed that there were 57 BP root avulsions in 29 patients. However, 2 T1 nerve root avulsions had been missed by pre-operative ultrasonography. Pathohistology revealed that all 8 BP root tumors pre-operatively diagnosed by ultrasonography were schwannomas. High-resolution ultrasonography can provide a convenient and accurate imaging modality for quick diagnosis and location of BP root lesions. PMID:24768481

Zhu, Yong-Sheng; Mu, Nan-Nan; Zheng, Min-Juan; Zhang, Yun-Chu; Feng, Hua; Cong, Rui; Zhou, Xiao-Dong; Chen, Ding-Zhang

2014-07-01

164

The distribution of acetylcholine in normal and in regenerating nerves.  

PubMed

1. The distribution of acetylcholine (ACh) in various nerves which had been regenerating for different periods after crushing has been compared with that in uncrushed nerves.2. Normal ventral roots from cats contained 78.1 +/- 22.7 (S.D.) mumole ACh/kg (blotted wet wt.); rabbit ventral roots contained 48.0 mumole/kg +/- 19.0 (S.D.) and rabbit sciatic nerves 16.6 +/- 7.3 (S.D.) mumole/kg. In the sciatic nerves the distal cm of 5 cm lengths taken from the thigh contained 30% more ACh than the most central cm portion. Possible explanations for this difference have been discussed.3. After both sciatic nerves and ventral roots had been crushed, there was an initial build-up (4 times control) of ACh central to the lesion and a decline ((1/4) control) distal to the lesion. These changes were maximum around 5 days after crushing. In sciatic nerves in which long periods of regeneration were investigated, the central build-up fell off to 1(1/2) times control by 25 days and the distal decline reversed to 2 times control in about 10 days. It then again decreased towards the control level by 25 days after crushing. These changes have been discussed in relation to the morphological changes which occur in a nerve following crushing.4. A peak of ACh content moved distally along the nerve from the crushed region at a rate of 1.0-1.5 mm/day. This was considered to represent an average rate of regeneration of the bulk of the axons. The amplitude of the peak declined progressively with time in the more distal parts of the nerve, probably because of dispersion as axons regenerated at different rates. PMID:6051808

Evans, C A; Saunders, N R

1967-09-01

165

Neurotization from two medial pectoral nerves to musculocutaneous nerve in a pediatric brachial plexus injury.  

PubMed

Traumatic brachial plexus injuries can be devastating, causing partial to total denervation of the muscles of the upper extremities. Surgical reconstruction can restore motor and/or sensory function following nerve injuries. Direct nerve-to-nerve transfers can provide a closer nerve source to the target muscle, thereby enhancing the quality and rate of recovery. Restoration of elbow flexion is the primary goal for patients with brachial plexus injuries. A 4-year-old right-hand-dominant male sustained a fracture of the left scapula in a car accident. He was treated conservatively. After the accident, he presented with motor weakness of the left upper extremity. Shoulder abduction was grade 3 and elbow flexor was grade 0. Hand function was intact. Nerve conduction studies and an electromyogram were performed, which revealed left lateral and posterior cord brachial plexopathy with axonotmesis. He was admitted to Rehabilitation Medicine and treated. However, marked neurological dysfunction in the left upper extremity was still observed. Six months after trauma, under general anesthesia with the patient in the supine position, the brachial plexus was explored through infraclavicular and supraclavicular incisions. Each terminal branch was confirmed by electrophysiology. Avulsion of the C5 roots and absence of usable stump proximally were confirmed intraoperatively. Under a microscope, neurotization from the musculocutaneous nerve to two medial pectoral nerves was performed with nylon 8-0. Physical treatment and electrostimulation started 2 weeks postoperatively. At a 3-month postoperative visit, evidence of reinnervation of the elbow flexors was observed. At his last follow-up, 2 years following trauma, the patient had recovered Medical Research Council (MRC) grade 4+ elbow flexors. We propose that neurotization from medial pectoral nerves to musculocutaneous nerve can be used successfully to restore elbow flexion in patients with brachial plexus injuries. PMID:23115676

Yu, Dong-Woo; Kim, Min-Su; Jung, Young-Jin; Kim, Seong-Ho

2012-09-01

166

Neurotization from Two Medial Pectoral Nerves to Musculocutaneous Nerve in a Pediatric Brachial Plexus Injury  

PubMed Central

Traumatic brachial plexus injuries can be devastating, causing partial to total denervation of the muscles of the upper extremities. Surgical reconstruction can restore motor and/or sensory function following nerve injuries. Direct nerve-to-nerve transfers can provide a closer nerve source to the target muscle, thereby enhancing the quality and rate of recovery. Restoration of elbow flexion is the primary goal for patients with brachial plexus injuries. A 4-year-old right-hand-dominant male sustained a fracture of the left scapula in a car accident. He was treated conservatively. After the accident, he presented with motor weakness of the left upper extremity. Shoulder abduction was grade 3 and elbow flexor was grade 0. Hand function was intact. Nerve conduction studies and an electromyogram were performed, which revealed left lateral and posterior cord brachial plexopathy with axonotmesis. He was admitted to Rehabilitation Medicine and treated. However, marked neurological dysfunction in the left upper extremity was still observed. Six months after trauma, under general anesthesia with the patient in the supine position, the brachial plexus was explored through infraclavicular and supraclavicular incisions. Each terminal branch was confirmed by electrophysiology. Avulsion of the C5 roots and absence of usable stump proximally were confirmed intraoperatively. Under a microscope, neurotization from the musculocutaneous nerve to two medial pectoral nerves was performed with nylon 8-0. Physical treatment and electrostimulation started 2 weeks postoperatively. At a 3-month postoperative visit, evidence of reinnervation of the elbow flexors was observed. At his last follow-up, 2 years following trauma, the patient had recovered Medical Research Council (MRC) grade 4+ elbow flexors. We propose that neurotization from medial pectoral nerves to musculocutaneous nerve can be used successfully to restore elbow flexion in patients with brachial plexus injuries.

Yu, Dong-Woo; Kim, Min-Su; Jung, Young-Jin

2012-01-01

167

SOFTWARE ENABLED VARIABLE DISPLACEMENT PUMPS  

Microsoft Academic Search

Direct pump control of hydraulic systems is more energy efficient than throttle valve based methods to control hydra ulic systems. This requires variable displacement pumps that are responsive and capable of electronic control. Such Electronic Displacement Controlled (EDC) pumps tend to be significantl y larger, heavier and more expensive than fixed displacement c oun- terparts. In addition, achievable control bandwidths

Perry Y. Li; Cassie Y. Li; Thomas R. Chase

168

DISPLACEMENT SPECTRA FOR SEISMIC DESIGN  

Microsoft Academic Search

Displacement-based seismic design and assessment of structures require the reliable definition of displacement spectra for a wide range of periods and damping levels. The displacement spectra derived from acceleration spectra in existing seismic codes do not provide a suitable answer and there are no existing frequency-dependent attenuation relationships derived specifically for this purpose. Using a carefully processed dataset of European

JULIAN J. BOMMER; AMR S. ELNASHAI

1999-01-01

169

Displacement Data Assimilation  

NASA Astrophysics Data System (ADS)

Geometric corrections are blended with nonlinear/non-Gaussian estimation methods to produced improved data assimilation outcomes on problems where features are critical. Problems of this sort are the estimation of hurricane tracks, tracking jet meandering, front propagation, among many others. The geometric correction is made possible by a data preserving map. It makes corrections on phase, primarily, as well as in the amplitude. The displacement assimilation is embedded in the analysis stage of a nonlinear/non-Gaussian Bayesian data assimilation scheme, such as the path integral method. In addition to showing how the method improves upon the results, as compared to more standard methodologies.

Restrepo, J. M.; Rosenthal, S.; Venkataramani, S.

2013-05-01

170

Gastric mucosal nerve density  

PubMed Central

Background: Autonomic neuropathy is a frequent diagnosis for the gastrointestinal symptoms or postural hypotension experienced by patients with longstanding diabetes. However, neuropathologic evidence to substantiate the diagnosis is limited. We hypothesized that quantification of nerves in gastric mucosa would confirm the presence of autonomic neuropathy. Methods: Mucosal biopsies from the stomach antrum and fundus were obtained during endoscopy from 15 healthy controls and 13 type 1 diabetic candidates for pancreas transplantation who had secondary diabetic complications affecting the eyes, kidneys, and nerves, including a diagnosis of gastroparesis. Neurologic status was evaluated by neurologic examination, nerve conduction studies, and skin biopsy. Biopsies were processed to quantify gastric mucosal nerves and epidermal nerves. Results: Gastric mucosal nerves from diabetic subjects had reduced density and abnormal morphology compared to control subjects (p < 0.05). The horizontal and vertical meshwork pattern of nerve fibers that normally extends from the base of gastric glands to the basal lamina underlying the epithelial surface was deficient in diabetic subjects. Eleven of the 13 diabetic patients had residual food in the stomach after overnight fasting. Neurologic abnormalities on clinical examination were found in 12 of 13 diabetic subjects and nerve conduction studies were abnormal in all patients. The epidermal nerve fiber density was deficient in skin biopsies from diabetic subjects. Conclusions: In this observational study, gastric mucosal nerves were abnormal in patients with type 1 diabetes with secondary complications and clinical evidence of gastroparesis. Gastric mucosal biopsy is a safe, practical method for histologic diagnosis of gastric autonomic neuropathy.

Selim, M.M.; Wendelschafer-Crabb, G.; Redmon, J.B.; Khoruts, A.; Hodges, J.S.; Koch, K.; Walk, D.; Kennedy, W.R.

2010-01-01

171

Optical stimulation of peripheral nerves in vivo  

NASA Astrophysics Data System (ADS)

This dissertation documents the emergence and validation of a new clinical tool that bridges the fields of biomedical optics and neuroscience. The research herein describes an innovative method for direct neurostimulation with pulsed infrared laser light. Safety and effectiveness of this technique are first demonstrated through functional stimulation of the rat sciatic nerve in vivo. The Holmium:YAG laser (lambda = 2.12 mum) is shown to operate at an optimal wavelength for peripheral nerve stimulation with advantages over standard electrical neural stimulation; including contact-free stimulation, high spatial selectivity, and lack of a stimulation artifact. The underlying biophysical mechanism responsible for transient optical nerve stimulation appears to be a small, absorption driven thermal gradient sustained at the axonal layer of nerve. Results explicitly prove that low frequency optical stimulation can reliably stimulate without resulting in tissue thermal damage. Based on the positive results from animal studies, these optimal laser parameters were utilized to move this research into the clinic with a combined safety and efficacy study in human subjects undergoing selective dorsal rhizotomy. The clinical Holmium:YAG laser was used to effectively stimulate human dorsal spinal roots and elicit functional muscle responses recorded during surgery without evidence of nerve damage. Overall these results predict that this technology can be a valuable clinical tool in various neurosurgical applications.

Wells, Jonathon D.

172

3D thermal model to investigate component displacement phenomenon during reflow soldering  

Microsoft Academic Search

This paper reports the development of a 3D component-level thermal model to investigate the displacement of the components during the reflow soldering process. One of the root causes of displacement is the temperature deviation between the contact surfaces of the components. Therefore, our model examines the temperature distribution at the level of discrete components and not at the level of

Balázs Illés; Gábor Harsányi

2008-01-01

173

Adapting to variable prismatic displacement  

NASA Technical Reports Server (NTRS)

In each of two studies, subjects were exposed to a continuously changing prismatic displacement with a mean value of 19 prism diopters (variable displacement) and to a fixed 19-diopter displacement (fixed displacement). In Experiment 1, significant adaptation (post-pre shifts in hand-eye coordination) was found for fixed, but not for variable, displacement. Experiment 2 demonstrated that adaptation was obtained for variable displacement, but it was very fragile and is lost if the measures of adaptation are preceded by even a very brief exposure of the hand to normal or near-normal vision. Contrary to the results of some previous studies, an increase in within-S dispersion was not found of target pointing responses as a result of exposure to variable displacement.

Welch, Robert B.; Cohen, Malcolm M.

1989-01-01

174

Nerve and Blood Vessels  

Microsoft Academic Search

From the histologic point of view, nerves are round or flattened cords, with a complex internal structure made of myelinated\\u000a and unmyelinated nerve fibers, containing axons and Schwann cells grouped in fascicles (Fig. 4.1a) (Erickson 1997). Along the course of the nerve, fibers can traverse from one fascicle to another and fascicles can split and merge. Based\\u000a on the fascicular

Maura Valle; Maria Pia Zamorani

175

Major peripheral nerve injuries.  

PubMed

Major peripheral nerve injuries in the upper extremities can result in significant morbidity. Understanding the pathophysiology of these injuries aids in the assessment and planning of appropriate treatment. With limited nerve mobilization, tension-free repairs can often be performed using sutures, fibrin glue, or nerve connectors. Acellular allograft and autograft reconstruction are better for bridging any gaps greater than a few millimeters. Adherence to proper principles of nerve repair improves the chances of achieving a favorable result, although in general these injuries portend a guarded prognosis. PMID:23895717

Isaacs, Jonathan

2013-08-01

176

Perineal Pudendal Neurotomy versus Selective Neurotomy of the S2 Somatic Contribution to the Pudendal Nerve  

Microsoft Academic Search

In 10 dogs that underwent bilateral electrode implantation on the S2 ventral root, 5 then underwent a bilateral total perineal neurotomy of the pudendal nerve (group A) at 3 months and 5 bilateral division of the S2 somatic contribution to the pudendal nerve (group B). The effects of these 2 types of neurotomy on the bladder and urethral responses to

Ruud J. L. H. Bosch; François Benard; Sherif R. Aboseif; Richard A. Schmidt; Emil A. Tanagho

1992-01-01

177

[Studies on the pudendal nerve. Part 4. A macroscopical observation of the branches of the pudendal plexus in dogs and cats (author's transl)].  

PubMed

The pudendal plexus and its branches of 20 dogs and 20 cats have been observed macroscopicaly. The main findings are summarized as follows: 1) The pudendal plexus in dogs is formed most frequently by the ventral rami of the first, second and third sacral nerves. 2) The bigeminal nerve of dogs and cats is formed respectively by the union of the ventral rami mentioned above. 3) The perineal nerve in dogs arises with one root from the bigeminal nerve and that of cats two roots, of which the main root arises from the points where the bigeminal nerve joins the asciatic nerve and the accessory one from the bigeminal nerve. 4) In dogs and cats the dorsal nerve of the penis or clitoris arises from the main trunk of the perineal nerve (Fig. 5, type IB) at an average rate of 57.5%. 5) In the dogs and cats, the inferior rectal nerve consists of two divisions; a division had the branches which are derived the perineal nerve to supply the skin around the anus and the other branches which arises from the muscular branch of the dorsal nerve of the penis or clitoris to supply the Sphincter ani externus. 6) The muscular branch of dogs and cats which is analogous to that of the perineal nerve in man, arises from the dorsal nerve of the penis or clitoris. 7) In dogs and cats the muscular branch to the Obturator internus is derived from the dorsal nerve of penis or clitoris. 8) The pelvic splanchnic nerve of dogs originates from the ventral rami of the first, second and third sacral nerves and that of cats from the ventral rami of the first and second sacral nerves. 9) In the posterior femoral cutaneous nerve in dogs, as well as in rats and rabbits, the lateral deviation of the origin from the sciatic to the perineal nerve is observed. PMID:1240085

Kanno, Y; Takasaki, S; Kaneshige, T; Nakanishi, T

1975-07-01

178

Entrapment of the Fifth Lumbar Spinal Nerve by Advanced Osteophytic Changes of the Lumbosacral Zygapophyseal Joint: A Case Report  

PubMed Central

A 54-year-old female patient had a 6-year history of backache and left sciatica. Five years earlier, she had undergone surgery in another hospital for left L4-5 disc herniation. Computed tomography revealed the ossified wall that enclosed the left L5 nerve root. There were also osteophytic changes in the left L5-S zygapophyseal joint. These osteophytes developed rostrally, along the left L5 nerve root, throug h the intervertebral foramina. We performed decompression surgery for the left L5 nerve root, and surgery resulted in symptomatic relief. We experienced a rare clinical presentation of osteophytic formation, with a specific configuration in relation to the nerve root. Surgeons should be aware of entrapment of the lumbar spinal nerve by advanced osteophytic changes occurring in the zygapophyseal joint after lumbar surgery.

Yuguchi, Takamichi; Iwatsuki, Koichi; Yoshimine, Toshiki

2012-01-01

179

Variable displacement blower  

DOEpatents

A blower having a stationary casing for rotatably supporting a rotor assembly having a series of open ended chambers arranged to close against the surrounding walls of the casing. Pistons are slidably mounted within each chamber with the center of rotation of the pistons being offset in regard to the center of rotation of the rotor assembly whereby the pistons reciprocate in the chambers as the rotor assembly turns. As inlet port communicates with the rotor assembly to deliver a working substance into the chamber as the pistons approach a top dead center position in the chamber while an outlet port also communicates with the rotor to exhaust the working substance as the pistons approach a bottom dead center position. The displacement of the blower is varied by adjusting the amount of eccentricity between the center of rotation of the pistons and the center of rotation of the rotor assembly.

Bookout, Charles C. (Niskayuna, NY) [Niskayuna, NY; Stotts, Robert E. (Clifton Park, NY) [Clifton Park, NY; Waring, Douglass R. (Ballston Spa, NY) [Ballston Spa, NY; Folsom, Lawrence R. (Ohain, BE) [Ohain, BE

1986-01-01

180

Displacement parameter inversion for a novel electromagnetic underground displacement sensor.  

PubMed

Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA). Based on that work, this paper presents an underground displacement inversion approach named "EELA forward modeling-approximate inversion method". Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0-100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications. PMID:24858960

Shentu, Nanying; Li, Qing; Li, Xiong; Tong, Renyuan; Shentu, Nankai; Jiang, Guoqing; Qiu, Guohua

2014-01-01

181

Displacement Parameter Inversion for a Novel Electromagnetic Underground Displacement Sensor  

PubMed Central

Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA). Based on that work, this paper presents an underground displacement inversion approach named “EELA forward modeling-approximate inversion method”. Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0–100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications.

Shentu, Nanying; Li, Qing; Li, Xiong; Tong, Renyuan; Shentu, Nankai; Jiang, Guoqing; Qiu, Guohua

2014-01-01

182

Schwannoma of Extraocular Nerves  

PubMed Central

An unusual case of schwannoma arising from the third cranial nerve in a thirteen year old male is reported. The patient presented with paresis of the right oculomotor nerve and ipsilateral hemiparesis. The clinical features of this case are discussed and the pertinent medical literature reviewed. ImagesFigure 1p220-bFigure 2Figure 3Figure 4Figure 5Figure 6

Niazi, Wasim; Boggan, James E.

1994-01-01

183

Peripheral nerve surgery.  

PubMed

In treating the three main surgical problems of peripheral nerves--nerve sheath tumors, entrapment neuropathies, and acute nerve injuries--the overriding consideration is the preservation and restoration of neurologic function. Because of this, certain other principles may need to be compromised. These include achieving a gross total excision of benign tumors, employing conservative therapy as long as a disease process is not clearly progressing, and delaying repair of a nerve transection until the skin wound has healed. Only three pathophysiologic processes need be considered: neurapraxia (focal segmental dymyelination), axonotmesis (wallerian degeneration caused by a lesion that does not disrupt fascicles of nerve fibers), and neurotmesis (wallerian degeneration caused by a lesion that interrupts fascicles). With nerve sheath tumors and entrapment neuropathies, the goal is minimize the extent to which neurapraxia progresses to axonotmesis. The compressive force is relieved without carrying out internal neurolysis, a procedure that is poorly tolerated, presumably because a degree of nerve ischemia exists with any long-standing compression. When the nerve has sustained blunt trauma (through acute compression, percussion, or traction), the result can be a total loss of function and an extensive neuroma-in-continuity (scarring within the nerve). However, the neural pathophysiology may amount to nothing more than axonotmesis. Although this lesion, in time, leads to full and spontaneous recovery, it must be differentiated from the neuroma-in-continuity that contains disrupted fascicles requiring surgery. Finally, with open nerve transection, the priority is to match the fascicles of the proximal stump with those of the distal stump, a goal that is best achieved if primary neurorrhaphy is carried out. PMID:2991727

McQuarrie, I G

1985-05-01

184

The nerve injury and the dying neurons: diagnosis and prevention.  

PubMed

Following distal nerve injury significant sensory neuronal cell death occurs in the dorsal root ganglia, while after a more proximal injury, such as brachial plexus injury, a sizeable proportion of spinal motoneurons also undergo cell death. This phenomenon has been undervalued for a long time, but it has a significant role in the lack of functional recuperation, as neuronal cells cannot divide and be replaced, hence the resulting nerve regeneration is usually suboptimal. It is now accepted that this cell death is due to apoptosis, as indicated by analysis of specific genes involved in the apoptotic signalling cascade. Immediate nerve repair, either by direct suturing or nerve grafting, gives a degree of neuroprotection, but this approach does not fully prevent neuronal cell death and importantly it is not always possible. Our work has shown that pharmacological intervention using either acetyl-L-carnitine (ALCAR) or N-acetyl-cysteine (NAC) give complete neuroprotection in different types of peripheral nerve injury. Both compounds are clinically safe and experimental work has defined the best dose, timing after injury and duration of administration. The efficacy of neuroprotection of ALCAR and NAC can be monitored non-invasively using MRI, as demonstrated experimentally and more recently by clinical studies of the volume of dorsal root ganglia. Translation to patients of this pharmacological intervention requires further work, but the available results indicate that this approach will help to secure a better functional outcome following peripheral nerve injury and repair. PMID:22058229

Terenghi, Giorgio; Hart, Andrew; Wiberg, Mikael

2011-11-01

185

The measurement of gas spaces in the roots of aquatic plants — Archimedes revisited  

Microsoft Academic Search

The volume of gas space within the root systems of pot-grown mangrove plants was determined by three methods based on Archimedes' principle: pycnometry, measurement of the upthrust on the root system when immersed in water, and measurement of the volume of water displaced. The results obtained using the upthrust and displacement methods were highly consistent. Although individual estimates obtained by

Mark Curran; Peter James; William G. Allaway

1996-01-01

186

A novel chondroitin sulfate hydrogel for nerve repair  

NASA Astrophysics Data System (ADS)

Brachial plexus injuries affect numerous patients every year, with very debilitating results. The majority of these cases are very severe, and involve damage to the nerve roots. To date, repair strategies for these injuries address only gross tissue damage, but do not supply cells with adequate regeneration signals. As a result, functional recovery is often severely lacking. Therefore, a chondroitin sulfate hydrogel that delivers neurotrophic signals to damaged neurons is proposed as a scaffold to support nerve root regeneration. Capillary electrophoresis studies revealed that chondroitin sulfate can physically bind with a variety of neurotrophic factors, and cultures of chick dorsal root ganglia demonstrated robust neurite outgrowth in chondroitin sulfate hydrogels. Outgrowth in chondroitin sulfate gels was greater than that observed in control gels of hyaluronic acid. Furthermore, the chondroitin sulfate hydrogel's binding activity with nerve growth factor could be enhanced by incorporation of a synthetic bioactive peptide, as revealed by fluorescence recovery after photobleaching. This enhanced binding was observed only in chondroitin sulfate gels, and not in hyaluronic acid control gels. This enhanced binding activity resulted in enhanced dorsal root ganglion neurite outgrowth in chondroitin sulfate gels. Finally, the growth of regenerating dorsal root ganglia in these gels was imaged using label-free coherent anti-Stokes scattering microscopy. This technique generated detailed, high-quality images of live dorsal root ganglion neurites, which were comparable to fixed, F-actin-stained samples. Taken together, these results demonstrate the viability of this chondroitin sulfate hydrogel to serve as an effective implantable scaffold to aid in nerve root regeneration.

Conovaloff, Aaron William

187

Correlation of peripheral displacement thresholds and optic disc parameters in ocular hypertension.  

PubMed Central

Both peripheral displacement thresholds and measurement of optic disc parameters have been advocated in the early diagnosis of glaucoma at the stage before scotomata are detected on conventional visual field assessment. The peripheral movement displacement thresholds were measured in 50 eyes of 50 patients with ocular hypertension and a significant correlation was found with neuroretinal rim areas measured using a computerised image system. There was also a significant correlation with optic disc diameter but no correlation with cup-disc ratio. The results support the proposition that measurement of peripheral movement displacement thresholds may be a useful tool in the detection of early glaucomatous optic nerve damage.

Ruben, S; Fitzke, F

1994-01-01

188

Mandibular nerve paresthesia caused by endodontic treatment.  

PubMed

The paresthesias of the inferior dental nerve consists of a complication that can occur after performing various dental procedures such as cystectomies, extraction of impacted teeth, apicoectomies, endodontic treatments, local anesthetic deposition, preprosthetic or implantologic surgery. The possible mechanisms of nervous lesions are mechanical, chemical and thermal. Mechanical injury includes compression, stretching, partial or total resection and laceration. The lesion can cause a discontinuity to the nerve with Wallerian degeneration of the distal and integrated fibers of the covering (axonotmesis) or can cause the total sectioning of the nerve (neurotmesis). Chemical trauma can be due to certain toxic components of the endodontic filling materials (paraformaldehyde, corticoids or eugenol) and irrigating solutions (sodium hypochlorite) or local anesthetics. Thermal injury is a consequence of bone overheating during the execution of surgical techniques. We present a clinical case of paresthesia of the inferior dental nerve after the introduction of a gutta-percha point in the mandibular canal during the performance of a root canal therapy of the inferior first molar. The etiology and the treatment of this endodontic complication are described. PMID:12937392

Gallas-Torreira, M Mercedes; Reboiras-López, M Dolores; García-García, Abel; Gándara-Rey, José

2003-01-01

189

Regenerative rotary displacer Stirling engine  

Microsoft Academic Search

A few rotary displacer Stirling engines whose displacers have one gas pocket space at one side, and rotate in a main enclosed cylinder, which is heated from one side and cooled from the opposite side without any regenerator have been tried and studied for a considerable time by the authors. They then tried to improve this engine by equipping them

Naotsugu Isshiki; Luca Raggi; S. Isshiki; K. Hirata; H. Watanabe

1996-01-01

190

Feature-based Displacement Mapping  

Microsoft Academic Search

Displacement mapping was originally created as a rendering tool to provide small-scale modulation of an underlying smooth surface. However, it has now emerged as a sculpting tool, to the extent that complex geometry can effectively be added to a scene at rendering time. The attendant complexity of displacement maps is placing increased demands on rendering systems, from quality, perfor- mance,

Xiaohuan Corina Wang; Jérôme Maillot; Eugene Fiume; Victor Ng-thow-hing; Andrew Woo; Sanjay Bakshi

2000-01-01

191

Is fibular fracture displacement consistent with tibiotalar displacement?  

PubMed

We believed open reduction with internal fixation is required for supination-external rotation ankle fractures located at the level of the distal tibiofibular syndesmosis (Lauge-Hanssen SER II and Weber B) with 2 mm or more fibular fracture displacement. The rationale for surgery for these ankle fractures is based on the notion of elevated intraarticular contact pressures with lateral displacement. To diagnose these injuries, we presumed that in patients with a fibular fracture with at least 2 mm fracture displacement, the lateral malleolus and talus have moved at least 2 mm in a lateral direction without medial displacement of the proximal fibula. We reviewed 55 adult patients treated operatively for a supination-external rotation II ankle fracture (2 mm or more fibular fracture displacement) between 1990 and 1998. On standard radiographs, distance from the tibia to the proximal fibula, distance from the tibia to the distal fibula, and displacement at the level of the fibular fracture were measured. These distances were compared preoperatively and postoperatively. We concluded tibiotalar displacement cannot be reliably assessed at the level of the fracture. Based on this and other studies, we believe there is little evidence to perform open reduction and internal fixation of supination-external rotation II ankle fractures. Level of Evidence: Level IV, case series. See Guidelines for Authors for a complete description of levels of evidence. PMID:19582527

van den Bekerom, Michel P J; van Dijk, C Niek

2010-04-01

192

Glossopharyngeal Nerve Schwannoma  

PubMed Central

Complete resection with conservation of cranial nerves is the primary goal of contemporary surgery for lower cranial nerve tumors. We describe the case of a patient with a schwannoma of the left glossopharyngeal nerve, operated on in our Neurosurgical Unit. The far lateral approach combined with laminectomy of the posterior arch of C1 was done in two steps. The procedure allowed total tumor resection and was found to be better than classic unilateral suboccipital or combined supra- and infratentorial approaches. The advantages and disadvantages of the far lateral transcondylar approach, compared to the other more common approaches, are discussed. ImagesFigure 1Figure 2

Puzzilli, F.; Mastronardi, L.; Agrillo, U.; Nardi, P.

1999-01-01

193

Bladder emptying by intermittent electrical stimulation of the pudendal nerve  

NASA Astrophysics Data System (ADS)

Persons with a suprasacral spinal cord injury cannot empty their bladder voluntarily. Bladder emptying can be restored by intermittent electrical stimulation of the sacral nerve roots (SR) to cause bladder contraction. However, this therapy requires sensory nerve transection to prevent dyssynergic contraction of the external urethral sphincter (EUS). Stimulation of the compound pudendal nerve trunk (PN) activates spinal micturition circuitry, leading to a reflex bladder contraction without a reflex EUS contraction. The present study determined if PN stimulation could produce bladder emptying without nerve transection in cats anesthetized with ?-chloralose. With all nerves intact, intermittent PN stimulation emptied the bladder (64 ± 14% of initial volume, n = 37 across six cats) more effectively than either distention-evoked micturition (40 ± 19%, p < 0.001, n = 27 across six cats) or bilateral intermittent SR stimulation (25 ± 23%, p < 0.005, n = 4 across two cats). After bilateral transection of the nerves innervating the urethral sphincter, intermittent SR stimulation voided 79 ± 17% (n = 12 across three cats), comparable to clinical results obtained with SR stimulation. Voiding via intermittent PN stimulation did not increase after neurotomy (p > 0.10), indicating that PN stimulation was not limited by bladder-sphincter dyssynergia. Intermittent PN stimulation holds promise for restoring bladder emptying following spinal injury without requiring nerve transection.

Boggs, Joseph W.; Wenzel, Brian J.; Gustafson, Kenneth J.; Grill, Warren M.

2006-03-01

194

[Nerve injuries and posttraumatic therapy].  

PubMed

Peripheral nerve injuries are a common clinical problem and can represent a major challenge, especially after trauma. In order to achieve optimal therapy, an early and adequate diagnosis with subsequent therapy is critical for functional preservation and restoration. Especially after complete severance of a peripheral nerve, the surgical techniques for nerve coaptation are an important prerequisite for peripheral nerve regeneration. The importance and necessity of adequate nerve coaptation and nerve transplantation are presented in detail. In addition, the types of primary and secondary nerve reconstruction procedures are described as well as the optimal time point of nerve repair. This article provides a comprehensive overview of the possibilities for diagnosis and intervention after nerve injury, additionally including an algorithm for surgical intervention. Furthermore, possible pitfalls and factors for improving the functional outcome are presented to optimize results with trauma-related nerve injury. PMID:24903504

Radtke, C; Vogt, P M

2014-06-01

195

Coding of position by simultaneously recorded sensory neurones in the cat dorsal root ganglion  

PubMed Central

Muscle, cutaneous and joint afferents continuously signal information about the position and movement of individual joints. How does the nervous system extract more global information, for example about the position of the foot in space? To study this question we used microelectrode arrays to record impulses simultaneously from up to 100 discriminable nerve cells in the L6 and L7 dorsal root ganglia (DRG) of the anaesthetized cat. When the hindlimb was displaced passively with a random trajectory, the firing rate of the neurones could be predicted from a linear sum of positions and velocities in Cartesian (x, y), polar or joint angular coordinates. The process could also be reversed to predict the kinematics of the limb from the firing rates of the neurones with an accuracy of 1–2 cm. Predictions of position and velocity could be combined to give an improved fit to limb position. Decoders trained using random movements successfully predicted cyclic movements and movements in which the limb was displaced from a central point to various positions in the periphery. A small number of highly informative neurones (6–8) could account for over 80% of the variance in position and a similar result was obtained in a realistic limb model. In conclusion, this work illustrates how populations of sensory receptors may encode a sense of limb position and how the firing of even a small number of neurones can be used to decode the position of the limb in space.

Stein, R B; Weber, D J; Aoyagi, Y; Prochazka, A; Wagenaar, J B M; Shoham, S; Normann, R A

2004-01-01

196

Sacral nerve stimulation.  

PubMed

The current concept of recruiting residual function of an inadequate pelvic organ by electrostimulation involves stimulation of the sacral spinal nerves at the level of the sacral canal. The rationale for applying SNS to fecal incontinence was based on clinical observations of its effect on bowel habits and anorectal continence function in urologic patients (increased anorectal angulation and anal canal closure pressure) and on anatomic considerations: dissection demonstrated a dual peripheral nerve supply of the striated pelvic floor muscles that govern these functions. Because the sacral spinal nerve site is the most distal common location of this dual nerve supply, stimulating here can elicit both functions. Since the first application of SNS in fecal incontinence in 1994, this technique has been improved, the patient selection process modified, and the spectrum of indications expanded. At present SNS has been applied in more than 1300 patients with fecal incontinence limited. PMID:15771288

Matzel, K E; Stadelmaier, U; Besendörfer, M

2004-01-01

197

Femoral nerve dysfunction  

MedlinePLUS

Felice, KJ. Focal neuropathies of the femoral, obturator, lateral femoral cutaneous and other nerves of the thigh and pelvis. In: Bromberg MB, Smith GA, eds. Handbook of Peripheral Neuropathy. Boca Raton, Fl: Taylor and Francis; 2005:chap ...

198

Lower cranial nerves.  

PubMed

Imaging evaluation of cranial neuropathies requires thorough knowledge of the anatomic, physiologic, and pathologic features of the cranial nerves, as well as detailed clinical information, which is necessary for tailoring the examinations, locating the abnormalities, and interpreting the imaging findings. This article provides clinical, anatomic, and radiological information on lower (7th to 12th) cranial nerves, along with high-resolution magnetic resonance images as a guide for optimal imaging technique, so as to improve the diagnosis of cranial neuropathy. PMID:24210311

Soldatos, Theodoros; Batra, Kiran; Blitz, Ari M; Chhabra, Avneesh

2014-02-01

199

[Multiple positional relationships of nerves arising from the sacral plexus to the piriformis muscle in humans].  

PubMed

The positional relationships between the piriformis muscle and the nerves which arise from the sacral nerve plexus were studied in 514 sides of 257 Japanese adults. These were classified into Types I-XIII and numerous subtypes based on: 1) the number of nerves perforating the piriformis muscle, 2) whether all or part of the nerve perforated the muscle, 3) the order of perforation and position in the muscle, and 4) communications between the nerves. In this paper, the multiple positional relations between the nerves and the piriformis muscle, the frequencies of the various types, and the order of priority concerning the perforation of nerves through the muscle are discussed. 1) The typical case, Type I, in which the piriformis muscle is not perforated by nerves except for a part of the superior gluteal nerve, was found in 309 (60%) of 514 sides. Types III-X, in which the muscle is perforated by additional nerves, were found in 195 sides (38%), and in 175 of these, all or part of the common peroneal nerve passed through the muscle. Types XI-XIII, in which the inferior gluteal nerve and other nerves pass above the piriformis muscle, were found in 10 sides (2%). Among all types, the following were generally seen: Type V, the piriformis muscle is perforated by both the inferior gluteal and common peroneal nerves; Type VII, the muscle is perforated by the two above-mentioned nerves and part of the posterior femoral cutaneous nerve (Fig. 16, Table 1). The common peroneal nerve followed two courses (a combination of over, through, and under the piriformis muscle) in 49 extremities. In the 4 cases of Type X (1%), the tibial nerve was divided into two components due to the intervention of the most caudal bundle of the piriformis or an unknown muscle. The dorsal component passed through the muscle, while the ventral component followed the typical course under the muscle (Figs. 9-11). Therefore, in the above-mentioned 53 cases as well as in other cases, the sacral nerve plexus cannot be divided into ventral and dorsal layers up to the sacral nerve roots, as in typical cases. Type II, in which the piriformis muscle is perforated by only a caudal branch of the superior gluteal nerve, was found in about 16% of 249 cases; this type was accompanied by some of the other types (Table 2). In the extraordinary case of Type XII with Type II, a branch of the superior gluteal nerve passed under the piriformis muscle (Fig. 13).(ABSTRACT TRUNCATED AT 400 WORDS) PMID:1296428

Chiba, S

1992-12-01

200

Role of the hypoglossal nerve in equine nasopharyngeal stability.  

PubMed

The equine upper airway is highly adapted to provide the extremely high oxygen demand associated with strenuous aerobic exercise in this species. The tongue musculature, innervated by the hypoglossal nerve, plays an important role in airway stability in humans who also have a highly adapted upper airway to allow speech. The role of the hypoglossal nerve in stabilizing the equine upper airway has not been established. Isolated tongues from eight mature horses were dissected to determine the distal anatomy and branching of the equine hypoglossal nerve. Using this information, a peripheral nerve location technique was used to perform bilateral block of the common trunk of the hypoglossal nerve in 10 horses. Each horse was subjected to two trials with bilateral hypoglossal nerve block and two control trials (unblocked). Upper airway stability at exercise was determined using videoendoscopy and measurement of tracheal and pharyngeal pressure. Three main nerve branches were identified, medial and lateral branches and a discrete branch that innervated the geniohyoid muscle alone. Bilateral hypoglossal block induced nasopharyngeal instability in 10/19 trials, and none of the control trials (0/18) resulted in instability (P<0.001). Mean treadmill speed (+/-SD) at the onset of instability was 10.8+/-2.5 m/s. Following its onset, nasopharyngeal instability persisted until the end of the treadmill test. This instability, induced by hypoglossal nerve block, produced an expiratory obstruction similar to that seen in a naturally occurring equine disease (dorsal displacement of the soft palate, DDSP) with reduced inspiratory and expiratory pharyngeal pressure and increased expiratory tracheal pressure. These data suggest that stability of the equine upper airway at exercise may be mediated through the hypoglossal nerve. Naturally occurring DDSP in the horse shares a number of anatomic similarities with obstructive sleep apnea. Study of species with extreme respiratory adaptation, such as the horse, may provide insight into respiratory functioning in humans. PMID:19498094

Cheetham, Jonathan; Pigott, John H; Hermanson, John W; Campoy, Luis; Soderholm, Leo V; Thorson, Lisa M; Ducharme, Norm G

2009-08-01

201

Borehole optical lateral displacement sensor  

DOEpatents

There is provided by this invention an optical displacement sensor that utilizes a reflective target connected to a surface to be monitored to reflect light from a light source such that the reflected light is received by a photoelectric transducer. The electric signal from the photoelectric transducer is then imputed into electronic circuitry to generate an electronic image of the target. The target`s image is monitored to determine the quantity and direction of any lateral displacement in the target`s image which represents lateral displacement in the surface being monitored. 4 figs.

Lewis, R.E.

1998-10-20

202

Restoration of diaphragmatic function after diaphragm reinnervation by inferior laryngeal nerve; experimental study in rabbits  

PubMed Central

Objectives To assess the possibilities of reinnervation in a paralyzed hemidiaphragm via an anastomosis between phrenic nerve and inferior laryngeal nerve in rabbits. Reinnervation of a paralyzed diaphragm could be an alternative to treat patients with ventilatory insufficiency due to upper cervical spine injuries. Material and method Rabbits were divided into five groups of seven rabbits each. Groups I and II were respectively the healthy and the denervated control groups. The 3 other groups were all reinnervated using three different surgical procedures. In groups III and IV, phrenic nerve was respectively anastomosed with the abductor branch of the inferior laryngeal nerve and with the trunk of the inferior laryngeal nerve. In group V, the fifth and fourth cervical roots were respectively anastomosed with the abductor branch of the inferior laryngeal nerve and with the nerve of the sternothyroid muscle (originating from the hypoglossal nerve). Animals were evaluated 4 months later using electromyography, transdiaphragmatic pressure measurements, sonomicrometry and histological examination. Results A poor inspiratory activity was found in quiet breathing in the reinnervated groups, with an increasing pattern of activity during effort. In the reinnervated groups, transdiaphragmatic pressure measurements and sonomicrometry were higher in group III with no significant differencewith groups IV and V. Conclusion Inspiratory contractility of an hemidiaphragm could be restored with immediate anastomosis after phrenic nerve section between phrenic nerve and inferior laryngeal nerve.

Derrey, Stephane; verin, Eric; Laquerriere, Annie; de Barros, Angelique Boishardy; Lacoume, Yann; Freger, Pierre; Marie, Jean Paul

2006-01-01

203

Correlation Analysis of Histomorphometry and Motor Neurography in the Median Nerve Rat Model  

PubMed Central

Objective: Standard methods to evaluate the functional regeneration after injury of the rat median nerve are insufficient to identify any further differences of axonal nerve regeneration after restitution of motor recovery is completed. An important complementary method for assessing such differences is a histomorphometric analysis of the distal to lesion nerve fibers. Recently, an electrophysiological method has been proposed as a sensitive method to examine the quality of axonal nerve regeneration. Methods: A linear regression analysis has been performed to correlate histomorphometric and neurographic data originating from 31 rats subjected to neurotmesis and immediate reconstruction of their right median nerve. Results: A significant linear correlation between the velocity of neuromuscular conduction and the total number of nerve fibers (P = .037) as well as between the amplitude of compound muscle action potential and the total number of nerve fibers (P = .026) has been identified. Interestingly, a significant correlation between the velocity of neuromuscular conduction and the square root of the cross-sectional area of the nerve could be found (P = .008). This corresponds to a linear correlation between the velocity of neuromuscular conduction and the radius of the nerve. Conclusion: These results contribute in a better interpretation of morphological predictors of nerve regeneration and verify the previously described electrophysiological assessment in the median nerve rat model as a valid method.

Manoli, Theodora; Werdin, Frank; Gruessinger, Hannes; Sinis, Nektarios; Schiefer, Jennifer Lynn; Jaminet, Patrick; Geuna, Stefano; Schaller, Hans-Eberhard

2014-01-01

204

Histological evaluation of mandibular third molar roots retrieved after coronectomy.  

PubMed

There is a resurgence of interest in coronectomy for the management of mandibular third molars because it has a low risk of injury to the inferior dental nerve. However, there is concern that the root that is left in place will eventually become a source of infection. We describe the histological evaluation of 26 consecutive symptomatic coronectomy roots in 21 patients. All roots had vital tissue in the pulp chamber and there was no evidence of periradicular inflammation. Persistent postoperative symptoms related predominantly to inflammation of the soft tissue, which was caused by partially erupted roots or failure of the socket to heal. PMID:24684971

Patel, Vinod; Sproat, Chris; Kwok, Jerry; Beneng, Kiran; Thavaraj, Selvam; McGurk, Mark

2014-05-01

205

Using CIDS with Displaced Workers.  

ERIC Educational Resources Information Center

Discusses the use of the Virginia Vital Information for Education and Work program at J. Sargeant Reynolds Community College, with particular emphasis on career planning and placement services and outreach efforts. Highlights special displaced workers programs with industry. (DMM)

Amburgey, Lillian; Sanborn, Carleton H.

1987-01-01

206

Polyimidazoles Via Aromatic Nucleophilic Displacement  

NASA Technical Reports Server (NTRS)

Experiments show variety of polyimidazoles prepared by aromatic nucleophilic displacement, from reactions of bisphenol imidazoles with activated difluoro compounds. Polyimidazoles have good mechanical properties making them suitable for use as films, moldings, and adhesives.

Connell, John W.; Hergenrother, Paul M.

1990-01-01

207

Pharmacological properties of a C-fibre response evoked by saphenous nerve stimulation in an isolated spinal cord-nerve preparation of the newborn rat.  

PubMed

1. An isolated spinal cord-peripheral nerve preparation of the newborn rat was developed. In this preparation it is possible to record spinal reflexes from a lumbar ventral root in response to stimulation of the ipsilateral saphenous or obturator nerve. 2. Single shock, weak intensity stimulation of the saphenous nerve induced a fast conducted compound action potential in the L3 dorsal root and a fast depolarizing response in the ipsilateral L3 ventral root. As a stronger stimulus was applied to the saphenous nerve, a slowly conducted compound action potential appeared in the dorsal root and a slow depolarizing ventral root potential (v.r.p.) in the L3 ventral root. 3. Single shock stimulation of the obturator nerve induced a rapidly conducted compound action potential in the L3 dorsal root and monosynaptic and polysynaptic reflexes, with a fast time course, in the ipsilateral L3 ventral root. 4. The slow v.r.p. evoked by saphenous nerve stimulation was depressed by the tachykinin antagonist, [D-Arg1, D-Trp7,9, Leu11] substance P (spantide), 4-16 microM. The response recovered its original shape and size 30-60 min after the removal of this antagonist. 5. The saphenous nerve-evoked slow v.r.p. was depressed by [Met5] enkephalin (0.1-1 microM), dynorphin (1-13)(0.2 microM) and morphine (1-2 microM), and these effects were reversed by naloxone (1 microM). 6. Two endogenous peptides, galanin (1-2 microM) and somatostatin (1-2.5 microM), inhibited the slow v.r.p. evoked by saphenous nerve stimulation, whereas another endogenous peptide, calcitonin gene-related peptide (0.1-0.5 microM), potentiated the slow v.r.p. The slow v.r.p. was also inhibited by gamma-aminobutyric acid (GABA, 20 microM) and muscimol (0.2 microM), and their effects were antagonized by bicuculline (1 microM). 7. The present results suggest that substance P and neurokinin A are involved in the saphenous nerve-evoked C-fibre response in the spinal cord of the newborn rat. PMID:2479438

Nussbaumer, J C; Yanagisawa, M; Otsuka, M

1989-10-01

208

Clavicle fracture with intrathoracic displacement.  

PubMed

Clavicle fractures are common, and most are isolated injuries. Injury to the nearby subclavian vessels and brachial plexus have classically been described as potential complications of clavicle fractures. However, in the setting of a substantially displaced clavicle fracture, concomitant thoracic trauma is relatively frequent. Injury to the thorax can be difficult to identify on physical examination, and advanced imaging modalities may be required for diagnosis. The evaluation, workup, and management of a patient with intrathoracic displacement of a clavicle fracture are described. Despite the significant fracture displacement and associated pneumothorax, the injury severity was not clinically obvious. Imaging, including a screening chest radiograph and subsequent axial computed tomography, played an important role in diagnosis and management. The patient underwent successful open reduction and plate fixation. A thoracostomy tube was not required at any point during the hospitalization. The patient recovered uneventfully and returned to full work duty by 3 months postoperatively. Including the current report, only 3 cases of intrathoracic displacement of the clavicle have been published in the English literature. All involved fractures of the middle third of the clavicle. The severity of displacement was not obvious in any patient, and diagnosis was dependent on additional imaging. Given the frequency of associated chest trauma and limitations of physical examination, chest radiography should be considered in the evaluation of patients with substantially displaced clavicle fractures. PMID:23937761

Lohse, Grant R; Lee, Donald H

2013-08-01

209

p75NGFR immunoreactivity in normal prenatal human dorsal root ganglia  

Microsoft Academic Search

The purpose of the present study was to examine immunohistochemically the expression of the low-affinity p75 nerve growth factor receptor in the dorsal root ganglia from 12 human fetuses (gestational ages, 10-24 weeks) located in three different spinal segments (cervical, thoracic, and lumbosacral), using a monoclonal mouse-antihuman low-affinity p75 nerve growth factor receptor antibody. The low-affinity p75 nerve growth factor

Mohammad Hossein Khorooshi; Birgit Fischer Hansen; Jean W Keeling; Dorrit S Nolting; Inger M Kjaer

2001-01-01

210

The Effect of Lodging in Cereals on Morphological Properties of the Root-Soil Complex  

Microsoft Academic Search

The permanent displacement of plant stems from the vertical, known as lodging, affects all cereal species and is a major limiting factor on grain production worldwide. Two forms of lodging are recognised: stem lodging (when the stem base buckles) and root lodging (when the root-soil system fails). However, there is conjecture about the mechanism of how the root-soil system fails.

A. R. Tams; S. J. Mooney; P. M. Berry

211

Spectral and spatial dependence of?diffuse optical signals in response to?peripheral nerve stimulation  

PubMed Central

Using non-invasive, near-infrared spectroscopy we have previously reported optical signals measured at or around peripheral nerves in response to their stimulation. Such optical signals featured amplitudes on the order of 0.1% and peaked about 100 ms after peripheral nerve stimulation in human subjects. Here, we report a study of the spatial and spectral dependence of the optical signals induced by stimulation of the human median and sural nerves, and observe that these optical signals are: (1) unlikely due to either dilation or constriction of blood vessels, (2) not associated with capillary bed hemoglobin, (3) likely due to blood vessel(s) displacement, and (4) unlikely due to fiber-skin optical coupling effects. We conclude that the most probable origin of the optical response to peripheral nerve stimulation is from displacement of blood vessels within the optically probed volume, as a result of muscle twitch in adjacent areas.

Chen, Debbie K.; Erb, M. Kelley; Tong, Yunjie; Yu, Yang; Sassaroli, Angelo; Bergethon, Peter R.; Fantini, Sergio

2010-01-01

212

Comparative morphological remarks on the origin of the posterior femoral cutaneous nerve.  

PubMed

The origin and course of the posterior femoral cutaneous nerve were observed macroscopically in 38 Japanese adult cadavers which were dissected in the University of Hokkaido, Faculty of Medicine during the years 1971/72 and the results obtained were compared with those from some other mammals (rat, rabbit, dog and cat) and a number of bibliographical findings on the other animals. On the basis of the archetype of the pudendal plexus, the site of origin of the posterior femoral cutaneous nerve was divided into seven portions as follows: the sciatic nerve or inferior gluteal nerve (I) and its originating roots (RI), the bigeminal nerve (B) and its originating roots (RB), the part of junction of I and B (CIB), the pudendal nerve (P) and its originating roots (RP). According to the arising mode, the posterior femoral cutaneous nerve was calssified into seven types: Type A (the sciatic nerve type); the nerve arises from I and RI (horse, rat, bird, frog and salamander). Type B (the sciatic transitional type); the nerve arises from I, RI, CIB, RB and B (MAN AND MONKEY). Type C (the bigeminal nerve type); the nerve arises from CIB, RB and B (gorilla, chimpanzee, orangutan, cat and sphenodon). Type D (the pudendal transitional type); the nerve arises from CIB, RB, B, RP and P (dog). Type E (the pudendal nerve type); the nerve arises from RP and P (pig, cattle and rabbit). Type F (the mixed type); a mixture of A to E types. These various patterns in the posterior femoral cutaneous nerve may be explained by the comparative anatomical explanation on the limb medial rotation given in Braus' text-book of Anatomy (Bd. I, S. 273). From these descriptions it is reasonable to presume that the main trunk of the posterior femoral cutaneous nerve of the tetrapod below the Aves arises from the sciatic nerve and is analogous to the gluteal branches of mammals, with its main stem still retained in the pudendal nerve. If the cutaneous area supplied by the posterior femoral cutaneous nerve expands to the lateral border of the buttock in company with the lower limb medial rotation, the part between this area and that supplied by the pudendal nerve is enlarged. At first, these expanded areas are probably supplied by the branches of the pudendal nerve, which gradually become independent to become the main stem of the posterior femoral cutaneous nerve in mammals. This nerve seems, therefore, to be primarily a division of the pedendal nerve, and so in man has various types of arising patterns, A to E, in accordance with the scheme in the phylogeny. Those hypothetical changes are observed in the human sacral plexus, from which the cutaneous nerve arises with a fan-shaped overlapping. PMID:1275304

Nakanishi, T; Kanno, Y; Kaneshige

1976-01-01

213

Hemifacial spasm caused by vascular compression of the distal portion of the facial nerve. Report of seven cases.  

PubMed

It is generally accepted that hemifacial spasm (HFS) and trigeminal neuralgia are caused by compression of the facial nerve (seventh cranial nerve) or the trigeminal nerve (fifth cranial nerve) at the nerve's root exit (or entry) zone (REZ); thus, neurosurgeons generally perform neurovascular decompression at the REZ. Neurosurgeons tend to ignore vascular compression at distal portions of the seventh cranial nerve, even when found incidentally while performing neurovascular decompression at the REZ of that nerve, because compression of distal portions of the seventh cranial nerve has not been regarded as a cause of HFS. Recently the authors treated seven cases of HFS in which compression of the distal portion of the seventh cranial nerve produced symptoms. The anterior inferior cerebellar artery (AICA) was the offending vessel in five of these cases. Great care must be taken not to stretch the internal auditory arteries during manipulation of the AICA because these small arteries are quite vulnerable to surgical manipulation and the patient may experience hearing loss postoperatively. It must be kept in mind that compression of distal portions of the seventh cranial nerve may be responsible for HFS in cases in which neurovascular compression at the REZ is not confirmed intraoperatively and in cases in which neurovascular decompression at the nerve's REZ does not cure HFS. Surgical procedures for decompression of the distal portion of the seventh cranial nerve as well as decompression at the REZ should be performed when a deep vascular groove is noticed at the distal site of compression of the nerve. PMID:9488322

Ryu, H; Yamamoto, S; Sugiyama, K; Uemura, K; Miyamoto, T

1998-03-01

214

Peripheral Nerve Sheath Tumors from Patients with Neurofibromatosis Type 1 Do Not Have the Chromosomal Translocation t(X;18)  

Microsoft Academic Search

Neurofibromatosis type 1 (NF1) is a common autosomal dominant genetic disorder that is caused by a mutation in the NF1 gene. Hallmark characteristics include dermal neurofibromas, café-au-lait spots, and learning disabilities. In approximately\\u000a 25% of NF1 cases, plexiform neurofibromas, or peripheral nerve sheath tumors (PNSTs) that involve large segments of nerve\\u000a sheath and nerve root, can form, of which a

Michael A. Liew; Cheryl M. Coffin; Jonathan A. Fletcher; Minh-Thu N. Hang; Katsumi Tanito; Michihito Niimura; David Viskochil

2002-01-01

215

ATF3 upregulation in glia during Wallerian degeneration: differential expression in peripheral nerves and CNS white matter  

Microsoft Academic Search

BACKGROUND: Many changes in gene expression occur in distal stumps of injured nerves but the transcriptional control of these events is poorly understood. We have examined the expression of the transcription factors ATF3 and c-Jun by non-neuronal cells during Wallerian degeneration following injury to sciatic nerves, dorsal roots and optic nerves of rats and mice, using immunohistochemistry and in situ

David Hunt; Kismet Hossain-Ibrahim; Matthew RJ Mason; Robert S Coffin; AR Lieberman; Julia Winterbottom; PN Anderson

2004-01-01

216

Optic nerve glioma: an update.  

PubMed

Optic nerve glioma is the most common optic nerve tumour. However, it has an unpredictable natural history. The treatment of optic nerve gliomas has changed considerably over the past few years. Chemotherapy and radiation therapy can now stabilize and in some cases improve the vision of patients with optic nerve gliomas. The treatment of optic nerve glioma requires a multi-disciplinary approach where all treatment options may have to be implemented in a highly individualized manner. The aim of this review article is to present current diagnostic and treatment protocols for optic nerve glioma. PMID:24736941

Nair, Akshay Gopinathan; Pathak, Rima S; Iyer, Veena R; Gandhi, Rashmin A

2014-08-01

217

Injection nerve palsy  

PubMed Central

Objective: To study the clinical profile and outcome of surgery for injection nerve palsies. Materials and Methods: This is a retrospective study of patients with INP who were treated at our institute during May 2000 to May 2009. Clinical, electroneuromyography (ENMG), and operative findings were noted. Intraoperative nerve action potential monitoring was not used in any case. Outcome of patients who were followed was reviewed. Results: INP comprised 92 (11%) of 837 nerve injury patients. Seventy one patients were children less than 16 years. The nerves involved were sciatic in 80 patients, radial in 8, and others in four. Fifty seven patients had power, grade 0/5. ENMG studies revealed absent compound muscle action potential in 64 and absent sensory nerve action potential in 67 patients. Thirty nine (42.3%) of 92 patients underwent surgery. The mean duration since injury in these patients was 5.2 months (3 months to 11 months). All underwent neurolysis. Only 18 patients who underwent surgery had a follow up of more than 3 months. Ten (55.5%) patients had good or fair outcome after surgery. Except for grade of motor deficit prior to surgery, none of the variables were found to significantly affect the outcome. Conclusion: The outcome of INP is generally good and many patients recover spontaneously. The outcome of surgery is dependent on preoperative motor power.

Kakati, Arindhom; Bhat, Dhananjaya; Devi, Bhagavathula Indira; Shukla, Dhaval

2013-01-01

218

Intrathecal TRESK gene recombinant adenovirus attenuates spared nerve injury-induced neuropathic pain in rats.  

PubMed

TRESK gene recombinant adenovirus (10 IU/ml), which has been constructed successfully in our previous study, was implemented through an intrathecal injection. The fact that the method can effectively upregulate the expression of TRESK mRNA in the dorsal root ganglia of spared nerve injury in rats was verified. We also investigated the role of TRESK gene recombinant adenovirus in attenuating tactile allodynia and thermal hyperalgesia in spared nerve injury rats. Spared nerve injury to the sciatic nerve induced persistent tactile allodynia, but had no effect on thermal hyperalgesia. Intrathecal injection of TRESK gene recombinant adenovirus (25 µl) into the region of lumbar enlargement in advance reduced tactile allodynia. Moreover, intrathecal injection of TRESK gene recombinant adenovirus (25 µl) significantly alleviated the activation of astrocytes in spinal cord induced by spared nerve injury. The current study shows that an intrathecal injection of the TRESK gene recombinant adenovirus attenuated the activity of astrocytes in spinal cord, which contributed to relieving neuropathic pain in spared nerve injury rats. According to the result reported in our previous study, attenuating the expression of TRESK in dorsal root ganglia was involved in the development of neuropathic pain. On the basis of these results, we theorized that the therapeutic utility of upregulation of TRESK in dorsal root ganglia was effective in relieving neuropathic pain syndromes induced by peripheral nerve injury. PMID:23370493

Zhou, Jun; Yang, Cheng-Xiang; Zhong, Ji-Ying; Wang, Han-Bing

2013-02-13

219

Lateral Entry Fixation Using Three Divergent Pins for Displaced Paediatric Supracondylar Humeral Fractures  

PubMed Central

Background. Supracondylar fractures are the commonest elbow injury in children. Most displaced supracondylar fractures are manipulated and held with a medial/lateral entry or two lateral Kirschner wires. This clinical study has results purely from a three lateral divergent wire technique. Methods. Displaced supracondylar fractures were manipulated closed and three lateral divergent wires inserted. Primary study end points were range of movement and carrying angle relative to the contralateral uninjured elbow (Flynn's grading system) and presence of iatrogenic nerve or vessel injury. Results. 25 children between 3 and 10 years (median 5, range 3–10) suffered a displaced fracture (15 type III, 10 type IIB). 15 left-, 10 right-sided fractures, 14 boys and 11 girls). 23 were fixed primarily, of these 21 in the first 24 hours. 2 were delayed due to swelling. 2 were fixed secondarily with lateral k-wires after loss of position (from a primarily fixed crossed wire technique). One radial and one median nerve palsy sustained at injury settled. No iatrogenic nerve injuries occurred. 21 Excellent, 3 good and 1 poor result on Flynn's grading. Conclusions. The use of three wires on the lateral side in this cohort showed no evidence of slip in fracture position and no iatrogenic nerve injury.

Guy, Stephen Paul; Ponnuru, Ramakrishna Rao; Gella, Sreenadh; Tulwa, Nirmal

2011-01-01

220

Displacement currents in geoelectromagnetic problems  

NASA Astrophysics Data System (ADS)

The influence of displacement currents in conventional geoelectromagnetic (GEM) methods using unimodal transversal electric (TE) or multimodal TE and TM (transversal magnetic) fields is only significant at very high frequencies in the frequency domain or at extremely early times in the time domain. The transient process in the latter includes three stages: the propagation through air, the propagation through earth and the diffusion within the earth. The influence of displacement currents is significant mainly during the former two stages, normally up to several tens to a few hundreds of nanoseconds. The behavior is essentially different in novel GEM methods using a vertical electric dipole (VED) or circular electric dipole (CED) sources of unimodal TM-fields. Under certain geoelectric conditions, the influence of displacement currents in these methods might be crucial at late times as well. This happens, if the model consists of insulating layers. In the absence of displacement currents, such layers would totally mask underlying structures. However, TM-fields including displacement currents depend on geoelectric parameters below insulating layers at late times.

Mogilatov, Vladimir; Goldman, Mark; Persova, Marina; Soloveichik, Yury

2014-06-01

221

The role of microsurgery in nerve repair and nerve grafting.  

PubMed

Advances in the field of microsurgery have improved the results after peripheral nerve surgery and have extended the types of nerve repair that can be accomplished. Innovative techniques using microsurgical dissection, such as nerve transfers and end-to-side repairs are direct consequences of these advances. PMID:17478254

Dvali, Linda; Mackinnon, Susan

2007-02-01

222

AN IN VITRO MODEL OF ADULT MAMMALIAN NERVE REPAIR  

PubMed Central

The role of pathway-derived growth factors in the support of peripheral axon regeneration remains elusive. Few appropriate knock-out mice are available, and gene silencing techniques are rarely 100% effective. To overcome these difficulties, we have developed an in vitro organotypic co-culture system that accurately models peripheral nerve repair in the adult mammal. Spinal cord sections from P4 mice that express YFP in their neurons are used to innervate segments of P4 peripheral nerve. This reconstructed ventral root is then transected and joined to a nerve graft. Growth of axons across the nerve repair and into the graft can be imaged repeatedly with fluorescence microscopy to define regeneration speed, and parent neurons can be labeled in retrograde fashion to identify contributing neurons. Nerve graft harvested from adult mice remains viable in culture by both morphologic and functional criteria. Motoneurons are supported with GDNF for the first week in culture, after which they survive axotomy, and are thus functionally adult. This platform can be modified by using motoneurons from any genetically modified mouse that can be bred to express XFP, by harvesting nerve graft from any source, or by treating the culture systemically with antibodies, growth factors, or pathway inhibitors. The regeneration environment is controlled to a degree not possible in vivo, and the use of experimental animals is reduced substantially. The flexibility and control offered by this technique should thus make it a useful tool for the study of regeneration biology.

Vyas, Alka; Li, Zhaobo; Aspalter, Manuela; Feiner, Jeffrey; Hoke, Ahmet; Zhou, Chunhua; O'Daly, Andres; Abdullah, Madeel; Rohde, Charles; Brushart, Thomas M.

2009-01-01

223

Prolonged nerve blockade delays the onset of neuropathic pain.  

PubMed

Aberrant neuronal activity in injured peripheral nerves is believed to be an important factor in the development of neuropathic pain. Pharmacological blockade of that activity has been shown to mitigate the onset of associated molecular events in the nervous system. However, results in preventing onset of pain behaviors by providing prolonged nerve blockade have been mixed. Furthermore, the experimental techniques used to date to provide that blockade were limited in clinical potential in that they would require surgical implantation. To address these issues, we have used liposomes (SDLs) containing saxitoxin (STX), a site 1 sodium channel blocker, and the glucocorticoid agonist dexamethasone to provide nerve blocks lasting ~1 wk from a single injection. This formulation is easily injected percutaneously. Animals undergoing spared nerve injury (SNI) developed mechanical allodynia in 1 wk; nerve blockade with a single dose of SDLs (duration of block 6.9 ± 1.2 d) delayed the onset of allodynia by 2 d. Treatment with three sequential SDL injections resulting in a nerve block duration of 18.1 ± 3.4 d delayed the onset of allodynia by 1 mo. This very prolonged blockade decreased activation of astrocytes in the lumbar dorsal horn of the spinal cord due to SNI. Changes in expression of injury-related genes due to SNI in the dorsal root ganglia were not affected by SDLs. These findings suggest that formulations of this kind, which could be easy to apply clinically, can mitigate the development of neuropathic pain. PMID:23045676

Shankarappa, Sahadev A; Tsui, Jonathan H; Kim, Kristine N; Reznor, Gally; Dohlman, Jenny C; Langer, Robert; Kohane, Daniel S

2012-10-23

224

Functional electrical stimulation of the left recurrent laryngeal nerve using a vagus nerve stimulator in a normal horse.  

PubMed

The aim of this study was to assess the feasibility of implanting an existing vagus nerve stimulating (VNS) electrode around the recurrent laryngeal nerve. The stimulus response characteristics required to achieve abduction of the ipsilateral arytenoid by the VNS electrode in the normal horse could then be determined. The electrode was wound around the left recurrent laryngeal nerve at the cervical level and connected to a pulse generator. Stimulus response characteristics were obtained by measuring stimulated arytenoid displacement endoscopically in the standing, non-sedated horse. A full and sustained abduction of the arytenoid was obtained with a stimulation frequency of 25 Hz and intensity of 1 mA with a pulse width of 250 ?s. PMID:20724182

Vanschandevijl, Katleen; Nollet, Heidi; Vonck, Kristl; Raedt, Rorecht; Boon, Paul; Roost, DirkVan; Martens, Ann; Deprez, Piet

2011-09-01

225

Dual pressure displacement control system  

SciTech Connect

This patent describes a dual pressure servo control system for a variable displacement hydraulic unit having displacement setting means positioned by a hydraulic servo mechanism. The hydraulic unit is provided with main loop lines at least one of which is capable of being subjected to high main loop pressure during operation of the hydraulic unit, a control line including a displacement control valve providing a controlled flow of fluid under pressure to the servo mechanism, and a source of fluid under pressure for the control line comprising a low pressure source connected to the control line through a check valve and high pressure source comprising of a high pressure control line connected to the control line downstream of the check valve. The high pressure control line includes a flow restriction limiting flow to the control line means and generating a significant flow induced pressure drop in the high pressure control line once movement in the servo mechanism is initiated.

Louis, J.E.; Klocke, C.C.

1988-02-02

226

Optic nerve hypoplasia in children.  

PubMed Central

Optic nerve hypoplasia (ONH) is characterised by a diminished number of optic nerve fibres in the optic nerve(s) and until recently was thought to be rare. It may be associated with a wide range of other congenital abnormalities. Its pathology, clinical features, and the conditions associated with it are reviewed. Neuroendocrine disorders should be actively sought in any infant or child with bilateral ONH. Early recognition of the disorder may in some cases be life saving. Images

Zeki, S. M.; Dutton, G. N.

1990-01-01

227

The association of octopamine with specific neurones along lobster nerve trunks.  

PubMed Central

Octapamine and its synthetic enzyme, tyramine beta-hydroxylase (TBH), are found in high concentrations at two points along second thoracic nerve roots in lobsters. The first is in the proximal section of the second root between the ventral nerve cord and the bifurcation of the root into medial (to flexor muscles) and lateral (to extensors) branches. The second region of high concentration is within a well known crustacean neurosecretory system, the pericardial organ, located close to the ends of the lateral branches of the roots. 2. With several different staining procedures, small clusters of nerve cell bodies are found within the connective tissue sheath in the proximal regions of the second roots. No cell bodies are seen in the pericardial organ regions. Cell bodies are variable in number and position between corresponding roots in the same animal and homologous roots among different animals. The average numbers of cell bodies, however, correlate well with TBH and octopamine content, and with the synthesis of octopamine in these same regions of roots. 3. Small clusters of root cell bodies dissected from preparations have greater than 500-fold higher activities of TBH than isolated efferent excitatory and inhibitory or afferent sensory axons. 4. Along with octopamine, the preferential synthesis of acetylcholine and serotonin is also seen in proximal segments of roots. Acetylcholine synthesis in these regions may represent transmitter synthesized in the nerve terminals innervating the root cells. The role of serotonin in these regions is not understood at this time but the amounts of endogenous serotonin found are only a tenth of the amounts of octopamine present. 5. Dopamine is not synthesized from tyrosine in second thoracic roots. However, if DOPA or dopamine are used as precursor compounds, then noradrenaline, which is usually not found in lobsters, can be accumulated in proximal segments of roots. 6. Phenolamines are converted to two further metabolites by lobster tissues. The compounds are unidentified and are named fast and slow product on the basis of their migration on electrophoresis at acid pH. Some partial characterization of slow product reveals that it is a mixture of compounds that can be converted on mild acid hydrolysis to fast product and the parent phenolamine. 7. The several lines of evidence presented suggest that nerve cells found in the proximal segments of the second thoracic roots contain and can synthesize octopamine. Since not all the cells in any single root have been analysed for octopamine or TBH, however, the possibility that one or more of the cells contain physiologically interesting substances other than octopamine is not eliminated. Images Plate 1 A B1, B2 C

Evans, P D; Kravitz, E A; Talamo, B R; Wallace, B G

1976-01-01

228

Extended Ane Root Systems  

Microsoft Academic Search

There are two notions of the extended ane root systems in the literature which both are introduced axiomatically. One, extended ane root system (SAERS for short), consists only of nonisotropic roots, while the other, extended ane root system (EARS for short), contains certain isotropic roots too. We show that there is a one to one correspondence between (reduced) SEARSs and

Saeid Azam

2002-01-01

229

Particle displacement tracking for PIV  

NASA Technical Reports Server (NTRS)

A new Particle Imaging Velocimetry (PIV) data acquisition and analysis system, which is an order of magnitude faster than any previously proposed system has been constructed and tested. The new Particle Displacement Tracing (PDT) system is an all electronic technique employing a video camera and a large memory buffer frame-grabber board. Using a simple encoding scheme, a time sequence of single exposure images are time coded into a single image and then processed to track particle displacements and determine velocity vectors. Application of the PDT technique to a counter-rotating vortex flow produced over 1100 velocity vectors in 110 seconds when processed on an 80386 PC.

Wernet, Mark P.

1990-01-01

230

Trigeminal root recording in normal trigeminal function.  

PubMed

Despite many investigations on the detection of trigeminal evoked potentials (TEP), there is still no consensus on a technique or interpretation of its components. In order to obtain clear TEP waveforms and analyze the origin of early components, we recorded TEP by the conventional far-field technique at the ipsilateral auricula as well as by near-field technique with a bipolar electrode at the trigeminal root just distal to the entry zone of its root. Trigeminal recordings were performed in nine patients with intrameatal vestibular schwannomas and in three with trigeminal neuralgia without trigeminal nerve deficits. In near-field recording at the trigeminal root, a triphasic response was recorded, with the first component occurring at 3.16 ms, 2.98 ms, and 4.16 ms following supraorbital, infraorbital, and mandibular nerve stimulation, respectively. Using conventional farfield TEP, the first component recorded at the trigeminal root occurred later than the first component in all other recordings. This suggests that the N2.0 component of far-field TEP is of extra-axial origin and the N5 component is of brainstem origin. The N13.0 component may be of cortical origin. We conclude that the N5.0 component and N5.0-N13.0 interpeak latency may be used as electrophysiological parameters of brainstem function during posterior fossa surgery. PMID:11485246

Naderi, S; Matthies, C; Samii, M

2001-07-01

231

Radiation Impairs Perineural Invasion by Modulating the Nerve Microenvironment  

PubMed Central

Purpose Perineural invasion (PNI) by cancer cells is an ominous clinical event that is associated with increased local recurrence and poor prognosis. Although radiation therapy (RT) may be delivered along the course of an invaded nerve, the mechanisms through which radiation may potentially control PNI remain undefined. Experimental Design An in vitro co-culture system of dorsal root ganglia (DRG) and pancreatic cancer cells was used as a model of PNI. An in vivo murine sciatic nerve model was used to study how RT to nerve or cancer affects nerve invasion by cancer. Results Cancer cell invasion of the DRG was partially dependent on DRG secretion of glial-derived neurotrophic factor (GDNF). A single 4 Gy dose of radiation to the DRG alone, cultured with non-radiated cancer cells, significantly inhibited PNI and was associated with decreased GDNF secretion but intact DRG viability. Radiation of cancer cells alone, co-cultured with non-radiated nerves, inhibited PNI through predominantly compromised cancer cell viability. In a murine model of PNI, a single 8 Gy dose of radiation to the sciatic nerve prior to implantation of non-radiated cancer cells resulted in decreased GDNF expression, decreased PNI by imaging and histology, and preservation of sciatic nerve motor function. Conclusions Radiation may impair PNI through not only direct effects on cancer cell viability, but also an independent interruption of paracrine mechanisms underlying PNI. RT modulation of the nerve microenvironment may decrease PNI, and hold significant therapeutic implications for RT dosing and field design for patients with cancers exhibiting PNI.

Bakst, Richard L.; Lee, Nancy; He, Shuangba; Chernichenko, Natalya; Chen, Chun-Hao; Linkov, Gary; Le, H. Carl; Koutcher, Jason; Vakiani, Efsevia; Wong, Richard J.

2012-01-01

232

Segmental thoracic lipomatosis of nerve with nerve territory overgrowth.  

PubMed

Lipomatosis of nerve (LN), or fibrolipomatous hamartoma, is a rare condition of fibrofatty enlargement of the peripheral nerves. It is associated with bony and soft tissue overgrowth in approximately one-third to two-thirds of cases. It most commonly affects the median nerve at the carpal tunnel or digital nerves in the hands and feet. The authors describe a patient with previously diagnosed hemihypertrophy of the trunk who had a history of large thoracic lipomas resected during infancy, a thoracic hump due to adipose proliferation within the thoracic paraspinal musculature, and scoliotic deformity. She had fatty infiltration in the thoracic spinal nerves on MRI, identical to findings pathognomonic of LN at better-known sites. Enlargement of the transverse processes at those levels and thickened ribs were also found. This case appears to be directly analogous to other instances of LN with overgrowth, except that this case involved axial nerves rather than the typical appendicular nerves. PMID:24506247

Mahan, Mark A; Amrami, Kimberly K; Howe, B Matthew; Spinner, Robert J

2014-05-01

233

Histochemical discrimination of fibers in regenerating rat infraorbital nerve  

NASA Technical Reports Server (NTRS)

In rat dorsal root ganglia, histochemical staining of carbonic anhydrase (CA) and cholinesterase (CE) yields a reciprocal pattern of activity: Sensory processes are CA positive and CE negative, whereas motor processes are CA negative and CE positive. In rat infraorbital nerve (a sensory peripheral nerve), we saw extensive CA staining of nearly 100% of the myelinated axons. Although CE reactivity in myelinated axons was extremely rare, we did observe CE staining of unmyelinated autonomic fibers. Four weeks after transection of infraorbital nerves, CA-stained longitudinal sections of the proximal stump demonstrated 3 distinct morphological zones. A fraction of the viable axons retained CA activity to within 2 mm of the distal extent of the stump, and the stain is capable of resolving growth sprouts being regenerated from these fibers. Staining of unmyelinated autonomic fibers in serial sections shows that CE activity was not retained as far distally as is the CA sensory staining.

Wilke, R. A.; Riley, D. A.; Sanger, J. R.

1992-01-01

234

Retraining Displaced Workers. Policy Brief  

ERIC Educational Resources Information Center

Robert LaLonde of the University of Chicago and Daniel Sullivan of the Federal Reserve Bank of Chicago suggest that retraining through our nation's community colleges is a way to reduce the skills gaps of at least some of these displaced workers and increase their reemployment earnings. Although workers may still experience significant earnings…

LaLonde, Robert; Sullivan, Daniel

2010-01-01

235

DISPLACEMENT BASED SEISMIC DESIGN METHODS.  

SciTech Connect

A research effort was undertaken to determine the need for any changes to USNRC's seismic regulatory practice to reflect the move, in the earthquake engineering community, toward using expected displacement rather than force (or stress) as the basis for assessing design adequacy. The research explored the extent to which displacement based seismic design methods, such as given in FEMA 273, could be useful for reviewing nuclear power stations. Two structures common to nuclear power plants were chosen to compare the results of the analysis models used. The first structure is a four-story frame structure with shear walls providing the primary lateral load system, referred herein as the shear wall model. The second structure is the turbine building of the Diablo Canyon nuclear power plant. The models were analyzed using both displacement based (pushover) analysis and nonlinear dynamic analysis. In addition, for the shear wall model an elastic analysis with ductility factors applied was also performed. The objectives of the work were to compare the results between the analyses, and to develop insights regarding the work that would be needed before the displacement based analysis methodology could be considered applicable to facilities licensed by the NRC. A summary of the research results, which were published in NUREGICR-6719 in July 2001, is presented in this paper.

HOFMAYER,C.MILLER,C.WANG,Y.COSTELLO,J.

2003-07-15

236

Prosthetic restoration after coronoradicular resection: Mechanical behavior of the distal root remaining and surrounding bone  

Microsoft Academic Search

Purpose. This 3-dimensional finite element analysis evaluated: (1) the mechanical behavior of the distal root remaining after resection of the mesial root in a mandibular molar; (2) the consequences of the remaining distal root displacements on the bone; and (3) the role of the radicular post in the transmission of stress to the remaining root.Methods. Three-dimensional finite element analysis was

Dominique Augereau; Laurent Pierrisnard; Patrick Renault; Michel Barquins

1998-01-01

237

Artemin induced functional recovery and reinnervation after partial nerve injury.  

PubMed

Systemic artemin promotes regeneration of dorsal roots to the spinal cord after crush injury. However, it is unclear whether systemic artemin can also promote peripheral nerve regeneration, and functional recovery after partial lesions distal to the dorsal root ganglion (DRG) remains unknown. In the present investigation, male Sprague Dawley rats received axotomy, ligation, or crush of the L5 spinal nerve or sham surgery. Starting the day of injury, animals received intermittent subcutaneous artemin or vehicle across 2weeks. Sensory thresholds to tactile or thermal stimuli were monitored for 6weeks after injury. Immunohistochemical analyses of the DRG and nerve regeneration were performed at the 6-week time point. Artemin transiently reversed tactile and thermal hypersensitivity after axotomy, ligation, or crush injury. Thermal and tactile hypersensitivity reemerged within 1week of treatment termination. However, artemin-treated rats with nerve crush, but not axotomy or ligation, subsequently showed gradual return of sensory thresholds to preinjury baseline levels by 6weeks after injury. Artemin normalized labeling for NF200, IB4, and CGRP in nerve fibers distal to the crush injury, suggesting persistent normalization of nerve crush-induced neurochemical changes. Sciatic and intradermal administration of dextran or cholera toxin B distal to the crush injury site resulted in labeling of neuronal profiles in the L5 DRG, suggesting regeneration functional restoration of nonmyelinated and myelinated fibers across the injury site into cutaneous tissue. Artemin also diminished ATF3 and caspase 3 expression in the L5 DRG, suggesting persistent neuroprotective actions. A limited period of artemin treatment elicits disease modification by promoting sensory reinnervation of distal territories and restoring preinjury sensory thresholds. PMID:24269493

Wang, Ruizhong; Rossomando, Anthony; Sah, Dinah W Y; Ossipov, Michael H; King, Tamara; Porreca, Frank

2014-03-01

238

Bilateral eventration of sciatic nerve.  

PubMed

During routine dissection of a 60 years male cadaver, it was observed that the two divisions of sciatic nerve were separate in the gluteal region on both the sides with the tibial nerve passing below the piriformis and the common peroneal nerve piercing the piriformis muscle. The abnormal passage of the sciatic nerve (SN), the common peroneal nerve (CPN), and the tibial nerve (TN), either through the piriformis or below the superior gemellus may facilitate compression of these nerves. Knowledge of such patterns is also important for surgeons dealing with piriformis syndrome which affects 5-6% of patients referred for the treatment of back and leg pain. A high division may also account for frequent failures reported with the popliteal block. PMID:22049898

Sharma, T; Singla, R K; Lalit, M

2010-01-01

239

Free displacer and Ringbom displacer for a Malone refrigerator  

SciTech Connect

Malone refrigeration uses a liquid near its critical point (instead of the customary gas) as the working fluid in a Stirling, Brayton, or similar regenerative or recuperative cycle. Thus far, we have focused on the Stirling cycle, to avoid the difficult construction of the high-pressure-difference counterflow recuperator required for a Brayton machine. Our first Malone refrigerator used liquid propylene (C{sub 3}H{sub 6}) in a double-acting 4-cylinder Stirling configuration. First measurements with a free displacer used in a liquid working fluid are presented. The displacer was operated both in harmonic mode and in Ringbom mode, in liquid carbon dioxide. The results are in reasonable agreement with expectations.

Swift, G.W.; Brown, A.O.

1994-05-01

240

The effect of precordial lead displacement on ECG morphology.  

PubMed

Inaccurate electrode placement and differences in inter-individual human anatomies can lead to misinterpretation of ECG examination. The aim of the study was to investigate the effect of precordial electrodes displacement on morphology of the ECG signal in a group of 60 patients with diagnosed cardiac disease. Shapes of ECG signals recorded from precordial leads were compared with signals interpolated at the points located at a distance up to 5 cm from lead location. Shape differences of the QRS and ST-T-U complexes were quantified using the distribution function method, correlation coefficient, root-mean-square error (RMSE), and normalized RMSE. The relative variability (RV) index was calculated to quantify inter-individual variability. ECG morphology changes were prominent in all shape parameters beyond 2 cm distance to precordial leads. Lead V2 was the most sensitive to displacement errors, followed by leads V3, V1, and V4, for which the direction of electrodes displacement plays a key role. No visible changes in ECG morphology were observed in leads V5 and V6, only scaling effect of signal amplitude. The RV ranged from 0.639 to 0.989. Distortions in ECG tracings increase with the distance from precordial lead, which are specific to chosen electrode, direction of displacement, and for ECG segment selected for calculations. PMID:24142562

Kania, Micha?; Rix, Hervé; Fereniec, Ma?gorzata; Zavala-Fernandez, Heriberto; Janusek, Dariusz; Mroczka, Tomasz; Stix, Günter; Maniewski, Roman

2014-02-01

241

Crustal Displacements Due to Continental Water Loading  

NASA Technical Reports Server (NTRS)

The effects of long-wavelength (> 100 km), seasonal variability in continental water storage on vertical crustal motions are assessed. The modeled vertical displacements (delta-r(sub M)) have root-mean-square (RMS) values for 1994-1998 as large as 8 mm with ranges up to 30 mm, and are predominantly annual in character. Regional strains are on the order of 20 nanostrain for tilt and 5 nanostrain for horizontal deformation. We compare delta-r(sub M) with observed Global Positioning System (GPS) heights (delta-r(sub O)) (which include adjustments to remove estimated effects of atmospheric pressure and annual tidal and non-tidal ocean loading) for 147 globally distributed sites. When the delta-r(sub O) time series are adjusted by delta-r(sub M), their variances are reduced, on average, by an amount equal to the variance of the delta-r(sub M). Of the delta-r(sub O) time series exhibiting a strong annual signal, more than half are found to have an annual harmonic that is in phase and of comparable amplitude with the annual harmonic in the delta-r(sub M). The delta-r(sub M) time series exhibit long-period variations that could be mistaken for secular tectonic trends or post-glacial rebound when observed over a time span of a few years.

vanDam, T.; Wahr, J.; Milly, P. C. D.; Shmakin, A. B.; Blewitt, G.; Lavallee, D.; Larson, K. M.

2001-01-01

242

Cyclic sciatica related to an extrapelvic endometriosis of the sciatic nerve: new concepts in surgical therapy.  

PubMed

Sciatic pain caused by endometriosis of the sciatic nerve is an uncommon clinical finding and seems to have been verified histologically in only a few cases. Patients complain of typical signs and symptoms of common sciatica that are cyclic in nature. Suggested compression of lumbar root or sciatic nerve or its plexus could be confirmed by electromyography, computed tomography, or magnetic resonance imaging, and by prompt response to hormonal suppression of ovarian function with regression of the radiologic findings. Patients often have required radical surgery with total hysterectomy and bilateral salpingo-oophorectomy. However, conservative surgery with excision of the endometriosis from the nerve can be successful in selected patients who wish to preserve reproductive function. We report a case of sciatic nerve involvement explored by magnetic resonance imaging, with endometriosis in contact with the nerve in the right sciatic trunk. PMID:12394671

Papapietro, N; Gulino, G; Zobel, B Beomonte Beomonte; Di Martino, A; Denaro, V

2002-10-01

243

The effects of elongation on the permeability and conduction characteristics of peripheral nerve  

SciTech Connect

The present studies analyze the effects of quasi-static tensile loading on the conduction and permeability characteristics of mouse sciatic nerve. Mechanical evaluations of nerve and roots were made via force and photographic records taken during elongation. Using strains to the proportional limit, functional properties of nerve were investigated. Recording of compound action potentials (CAP) during stretch yielded reductions in CAP velocity, slope, and area. Increments were observed in rise time, fall time, and duration. Vascular permeability was investigated for identical strains. SDS-PAGE analyses of nerve proteins yielded minimal changes in albumin concentration with stretch. Paper chromatography analyses of endoneurial fluid showed increments in amino acid concentrations during stretch. Perineurium permeability was studied using radiolabel techniques. Nerve stretch resulted in increased {sup 14}C-dextran accumulation at higher strains with additional accumulation during relaxation. Perineurial permeability increases were attributed to expansion of perineurial holes during stretch.

Beel, J.A.

1989-01-01

244

Ultrasound of Peripheral Nerves  

PubMed Central

Over the last decade, neuromuscular ultrasound has emerged as a useful tool for the diagnosis of peripheral nerve disorders. This article reviews sonographic findings of normal nerves including key quantitative ultrasound measurements that are helpful in the evaluation of focal and possibly generalized peripheral neuropathies. It also discusses several recent papers outlining the evidence base for the use of this technology, as well as new findings in compressive, traumatic, and generalized neuropathies. Ultrasound is well suited for use in electrodiagnostic laboratories where physicians, experienced in both the clinical evaluation of patients and the application of hands-on technology, can integrate findings from the patient’s history, physical examination, electrophysiological studies, and imaging for diagnosis and management.

Suk, Jung Im; Walker, Francis O.; Cartwright, Michael S.

2013-01-01

245

Possible role of alpha-lipoic acid in the treatment of peripheral nerve injuries  

PubMed Central

Recent findings on the antioxidant effects of pretreatment with ?-lipoic acid (?-LA) on the crush injury of rat sciatic nerve confirm the possible usefulness of ?-LA administration in humans with peripheral nerve injuries. We discussed this issue in relation with our recent results in which the combined employment of ?-LA and ?-linolenic acid with a rehabilitation program for six weeks reduced sensory symptoms and neuropathic pain in patients with compressive radiculopathy syndrome from disc-nerve root conflict in comparison with patients submitted to rehabilitation program alone for six weeks.

2010-01-01

246

Intrinsic arteriovenous malformation embedded in the trigeminal nerve of a patient with trigeminal neuralgia.  

PubMed

A 66-year-old man presented with typical right trigeminal neuralgia. Neuroimaging showed a small arteriovenous malformation (AVM) in the right cerebellopontine angle. Suboccipital craniotomy verified that the AVM was almost completely embedded in the root entry zone of the trigeminal nerve and the nerve axis was tilted infero-posteriorly. The patient obtained complete pain relief without sequelae after surgery by transposition of the superior cerebellar artery and correction of the tilted nerve axis. The nidus of the unresected AVM was obliterated by gamma knife radiosurgery. PMID:21946727

Sumioka, Shinya; Kondo, Akinori; Tanabe, Hideki; Yasuda, Soichiro

2011-01-01

247

Sixth cranial nerve palsy caused by compression from a dolichoectatic vertebral artery.  

PubMed

A 68-year-old man had an unremitting left sixth cranial nerve palsy immediately after completing a long bicycle trip. High-resolution (3 Tesla) magnetic resonance imaging disclosed a dolichoectatic vertebral artery that compressed the left sixth cranial nerve against the belly of the pons at its root exit zone. It was postulated that increased blood flow in the vessel during the unusually prolonged aerobic exercise precipitated the palsy. Compressive palsies of cranial nerves caused by a dolichoectatic basilar artery have often been documented; compressive palsy caused by a dolichoectatic vertebral artery is less well-recognized. PMID:15937439

Zhu, Ying; Thulborn, Keith; Curnyn, Kimberlee; Goodwin, James

2005-06-01

248

Oxaliplatin induces hypomyelination and reduced neuregulin 1 expression in the rat sciatic nerve.  

PubMed

Oxaliplatin causes severe peripheral neuropathy. In this study, we examined hypomyelination in the peripheral nerve in oxaliplatin-induced neuropathy rat model. Gene expression of neuregulin 1 (NRG1), a myelination regulatory factor, is reduced in the dorsal root ganglion (DRG) in DNA microarray analysis. Oxaliplatin increased the g-ratio and reduced levels of myelin protein zero in sciatic nerve, suggesting the hypomyelination. Moreover, oxaliplatin reduced NRG1 mRNA levels in the DRG and decreased levels of cleaved NRG1 type III protein in the sciatic nerve. Our results indicate that oxaliplatin induces hypomyelination and reduced NRG1 expression. PMID:24530887

Tsutsumi, Kuniaki; Yamashita, Yuji; Ushio, Soichiro; Kawashiri, Takehiro; Kaname, Takanori; Fujita, Shunsuke; Oishi, Ryozo; Egashira, Nobuaki

2014-03-01

249

Peripheral Nerve Tumors  

Microsoft Academic Search

\\u000a Peripheral nerve tumors (PNTs) are rare soft tissue lesions that can arise anywhere on the body and as a result have a wide\\u000a differential diagnosis, which is often confirmed to be a PNT only at surgery. PNTs occur both sporadically and within the\\u000a context of genetically predisposing syndromes; hence, a thorough history of the mass and associated symptoms, with a

Joseph Wiley; Asis Kumar Bhattacharyya; Gelareh Zadeh; Patrick Shannon; Abhijit Guha

250

Cranial Nerve II: Vision.  

PubMed

This article contains a brief review of the anatomy of the visual system, a survey of diseases of the retina, optic nerve and lesions of the optic chiasm, and other visual field defects of special interest to the psychiatrist. It also includes a presentation of the corticothalamic mechanisms, differential diagnosis, and various manifestations of visual illusions, and simple and complex visual hallucinations, as well as the differential diagnoses of these various visual phenomena. PMID:19855858

Gillig, Paulette Marie; Sanders, Richard D

2009-09-01

251

Epidermal nerve fibers  

PubMed Central

Objectives: Our first objective was to explore the value of estimating 95% confidence intervals (CIs) of epidermal nerve fibers (ENFs)/mm for number of sections to be evaluated and for confidently judging normality or abnormality. Our second objective was to introduce a new continuous measure combining nerve conduction and ENFs/mm. Methods: The 95% CI studies were performed on 1, 1–2, 1–3 - - - 1–10 serial skip sections of 3-mm punch biopsies of leg and thigh of 67 healthy subjects and 23 patients with diabetes mellitus. Results: Variability of differences of ENFs/mm counts (and 95% CIs) from evaluation of 1, 1–2, 1–3 - - - 1–9 compared with 1–10 serial skip sections decreased progressively without a break point with increasing numbers of sections evaluated. Estimating 95% CIs as sections are evaluated can be used to judge how many sections are needed for adequate evaluation, i.e., only a few when counts and 95% CIs are well within the range of normality or abnormality and more when values are borderline. Also provided is a methodology to combine results of nerve conduction and ENFs/mm as continuous measures of normality or abnormality. Conclusion: Estimating 95% CIs of ENFs/mm is useful to judge how many sections should be evaluated to confidently declare counts to be normal or abnormal. Also introduced is a continuous measure of both large-fiber (nerve conduction) and small-fiber (ENFs/mm) normal structures/functions spanning the range of normality and abnormality for use in therapeutic trials.

Engelstad, JaNean K.; Taylor, Sean W.; Witt, Lawrence V.; Hoebing, Belinda J.; Herrmann, David N.; Klein, Christopher J.; Johnson, David M.; Davies, Jenny L.; Carter, Rickey E.

2012-01-01

252

The role of nerve allografts and conduits for nerve injuries.  

PubMed

Nerve repair after transection has variable and unpredictable outcomes. In addition to advancements in microvascular surgical techniques, nerve allografts and conduits are available options in peripheral nerve reconstruction. When tensionless nerve repair is not feasible, or in chronic injuries, autografts have been traditionally used. As substitute to autografts, decellularized allografts and conduits have become available. These conduits can reduce donor site morbidity, functional loss at the donor area in cases where autografts are used, and immune reaction from transplants or unprocessed allografts. The development of new biomaterials for use in conduits, as well as use of cytokines, growth factors, and other luminal fillers, may help in the treatment of acute and chronic nerve injuries. The indications and properties of nerve conduits and allografts are detailed in this article. PMID:20670808

Rivlin, Michael; Sheikh, Emran; Isaac, Roman; Beredjiklian, Pedro K

2010-08-01

253

Polyphenylquinoxalines via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

Polyphenylquinoxalines are prepared by the nucleophilic displacement reaction of di(hydroxyphenyl)quinoxaline monomers with activated aromatic dihalides or dinitro compounds. The reactions are carried out in polar aprotic solvents during alkali metal bases at elevated temperatures under nitrogen. The di(hydroxyphenyl)quinoxaline monomers are prepared either by reacting stoichiometric quantities of aromatic bis(o-diamines) with a hydroxybenzil or by reacting o-phenylenediamine with a dihydroxybenzil or bis(hydroxyphenylglyoxylyl)benzene.

Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor)

1991-01-01

254

Polyphenylquinoxalines via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

Polyphenylquinoxalines are prepared by the nucleophilic displacement reaction of di(hydroxyphenyl)quinoxaline monomers with activated aromatic dihalides or dinitro compounds. The reactions are carried out in polar aprotic solvents using alkali metal bases at elevated temperatures under nitrogen. The di(hydroxyphenyl)quinoxaline monomers are prepared either by reacting stoichiometric quantities of aromatic bis(o-diamines) with a hydroxybenzil or by reacting o-phenylenediamine with a dihydroxybenzil or bis(hydroxyphenylglyoxylyl)benzene.

Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor)

1990-01-01

255

Polybenzimidazole via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

Di(hydroxyphenyl)benzimidazole monomers were prepared from phenyl-4-hydroxybenzoate and aromatic bis(o-diamine)s. These monomers were used in the synthesis of soluble polybenzimidazoles. The reaction involved the aromatic nucleophilic displacement of various di(hydroxyphenyl)benzimidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds in the presence of an alkali metal base. These polymers exhibited lower glass transition temperatures, improved solubility, and better compression moldability over their commercial counterparts.

Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Joseph G. (Inventor)

1994-01-01

256

[Regeneration of perivascular nerve and role of angiotensin receptors].  

PubMed

The present study was designed to investigate involvement of angiotensin (Ang) II type 2 receptors (AT2R) in restoration of perivascular nerve innervation injured by topical phenol treatment. Male Wistar rats underwent in vivo topical application of 10% phenol around the superior mesenteric artery to induce nerve injure. Phenol treatment markedly reduced densities of both calcitonin gene-related peptide (CGRP)-like immunoreactivity (LI)- and neuropeptide Y (NPY)-LI-containing fibers. NGF restored densities of both nerve fibers to the Sham control level. Coadministration of Ang II and losartan (AT1R antagonist) significantly increased the density of CGRP-LI-fibers but not NPY-LI-fibers compared with saline control. The increase of the density of CGRP-LI-fibers by coadministration of Ang II and losartan was suppressed by adding PD123319 (AT2R antagonist). Furthermore, NGF-induced CGRP-LI nerve regeneration was inhibited by PD123319 treatment. NGF-induced increase of AT2R mRNA level was significantly suppressed by AT1R antagonist treatment in phenol treated rats dorsal root ganglia. These results suggest that selective stimulation of AT2R by Ang II facilitates reinnervation of mesenteric perivascular CGRP-containing nerves injured by topical phenol application in the rat. PMID:20823676

Hobara, Narumi; Goda, Mitsuhiro; Yoshida, Namika; Hashikawa, Naoya; Kawasaki, Hiromu

2010-09-01

257

Biosynthesis and transport of gangliosides in peripheral nerve  

SciTech Connect

Radiolabelled glucosamine was injected into L-7 dorsal root ganglion (DRG) of rabbits. At several different times after injection DRG, lumbosacral trunks (LST) and sciatic nerves (SN) were removed and gangliosides extracted. Two and 3 weeks after injection the amounts of radioactivity in the ganglioside fractions of LST and SN were significantly higher than at days 1 and 2. The TCA soluble radioactivity decreased dramatically over the same time period. Colchicine prevented the appearance of radiolabelled lipid in LST and SN. From these experiments the authors conclude that some ganglioside is synthesized in the neuronal cell bodies of DRG and transported in the axons of the sciatic nerve. In another experiment the sciatic nerve was transected and ends separated to prevent regeneration. There was no difference in the amount of radiolabelled ganglioside that was isolated from DRG or LST of transected nerves compared with control nerves. The behavior of several potential acid soluble contaminants was studied in several steps used to isolate gangliosides. Of those studied only CMP-NeuAc could cause significant contamination of the final ganglioside preparation.

Yates, A.J.; Tipnis, U.R.; Hofteig, J.H.; Warner, J.K.

1984-01-01

258

Transgenic hairy roots  

Microsoft Academic Search

Agrobacterium rhizogenes causes hairy root disease in plants. The neoplastic roots produced by A. rhizogenes infection is characterized by high growth rate and genetic stability. These genetically transformed root cultures can produce higher levels of secondary metabolites or amounts comparable to that of intact plants. Hairy root cultures offer promise for production of valuable secondary metabolites in many plants. The

Archana Giri; M. Lakshmi Narasu

2000-01-01

259

Effect of arecoline on regeneration of injured peripheral nerves.  

PubMed

The present study provides in vitro and in vivo evaluation of arecoline on peripheral nerve regeneration. In the in vitro study, we found that arecoline at 50 ?g/ml could significantly promote the survival and outgrowth of cultured Schwann cells as compared to the controls treated with culture medium only. In the in vivo study, we evaluated peripheral nerve regeneration across a 10-mm gap in the sciatic nerve of the rat, using a silicone rubber nerve chamber filled with the arecoline solution. In the control group, the chambers were filled with normal saline only. At the end of the fourth week, morphometric data revealed that the arecoline-treated group at 5 ?g/ml significantly increased the number and the density of myelinated axons as compared to the controls. Immunohistochemical staining in the arecoline-treated animals at 5 ?g/ml also showed their neural cells in the L4 and L5 dorsal root ganglia ipsilateral to the injury were strongly retrograde-labeled with fluorogold and lamina I-II regions in the dorsal horn ipsilateral to the injury were significantly calcitonin gene-related peptide-immunolabeled compared with the controls. In addition, we found that the number of macrophages recruited in the distal sciatic nerve was increased as the concentration of arecoline was increased. Electrophysiological measurements showed the arecoline-treated groups at 5 and 50 ?g/ml had a relatively larger nerve conductive velocity of the evoked muscle action potentials compared to the controls. These results indicate that arecoline could stimulate local inflammatory conditions, improving the recovery of a severe peripheral nerve injury. PMID:23895157

Lee, Sheng-Chi; Tsai, Chin-Chuan; Yao, Chun-Hsu; Hsu, Yuan-Man; Chen, Yueh-Sheng; Wu, Ming-Chang

2013-01-01

260

Gravitropic curvature of maize roots is not preceded by rootcap asymmetry  

NASA Technical Reports Server (NTRS)

We tested whether the first response to gravistimulation is an asymmetry in the root tip that results from differential growth of the rootcap itself. The displacement of markers on the rootcap surface of maize (Zea mays L. cv. Merit) roots was quantified from videotaped images using customized software. The method was sensitive enough to detect marker displacements down to 15 microns and root curvature as early as 8 min after gravistimulation. No differential growth of the upper and lower sides of the cap occurred before or during root curvature. Fewer than a third of all gravistimulated roots developed an asymmetrical outline of the root tip after curvature had started, and this asymmetry did not occur in the rootcap itself. Our data support the view that the regions of gravitropic sensing and curvature are spatially separate during all phases of gravitropism in maize roots.

Sack, F. D.; Hasenstein, K. H.; Blair, A.

1990-01-01

261

Nerve stimulator guided pudendal nerve block decreases posthemorrhoidectomy pain  

Microsoft Academic Search

Purpose  Based on our institution’s initial results that reflected reduced postoperative pain using a modified pudendal nerve block\\u000a technique, we conducted a prospective, randomized, double-blind study to investigate whether a combination of general anesthesia\\u000a and bilateral nerve stimulator guided pudendal nerve blocks could provide better postoperative pain relief compared to general\\u000a anesthesia alone or in combination with placebo nerve blocks.\\u000a \\u000a \\u000a \\u000a Methods  Following

Zouheir Naja; Mohammad Fouad Ziade; Per-Arne Lönnqvist

2005-01-01

262

Somato-motor components of the pelvic and pudendal nerves of the female rat.  

PubMed

The efferent innervation of the pelvic and pudendal nerves was characterized in this study by identifying the muscles activated by electrical stimulation of the nerves distal to the point at which they bifurcate from the L6-S1 trunk. Pelvic nerve electrical stimulation produced EMG-monitored contraction of the ipsilateral ilio- and pubococcygeus muscles, which was abolished by cutting one ('muscular') branch of the bifurcated nerve. (This 'muscular' branch receives proprioceptive input activated by tail displacement, whereas the other, 'viscero-cutaneous' branch receives sensory innervation from the midline perineal region.) Pudendal nerve electrical stimulation produced contraction of the coccygeus, external anal sphincter, and ischiocavernosus muscles. Movements of the orifice and wall of the vagina were directly visualized during electrical stimulation of the two nerves. Intravaginal pressure measured by balloon was increased by pelvic nerve stimulation and decreased by pudendal nerve stimulation. Reflexive contraction of the ilio- en pubococcygeus muscles was produced by mechanostimulation of the perineum, clitoral sheath and distal vagina. This response was abolished by gentle cervical mechanostimulation. One implication of this finding is that passage of the fetuses through the cervix during parturition may relax the ilio- and pubococcygeus muscles, thereby facilitating delivery. PMID:2758331

Pacheco, P; Martinez-Gomez, M; Whipple, B; Beyer, C; Komisaruk, B R

1989-06-19

263

ON THE ORIGINS OF DORSAL ROOT POTENTIALS  

PubMed Central

The "dorsal root potential" consists of five successive deflections designated for convenience, D.R.I, II, III, IV, and V. Of these, D.R.V alone constitutes the dorsal root potential of prior description. A study has been made of the general properties of those deflections not previously described. Dorsal root potentials are electrotonic extensions into the extramedullary root segment, the result of electrical interactions within the cord comparable to those that have been studied in peripheral nerve. Although the anatomical and electrical conditions of interaction are infinitely more complex in the cord than in nerve, it is seen that the fact of parallel distribution of primary afferent fibers pertaining to neighboring dorsal roots provides a sufficient anatomical basis for qualitative analysis in the first approximation of dorsal root potentials. An extension of the theory of interaction between neighboring nerve fibers has been made to include an especial case of interaction between fibers orientated at right angles to one another. The predictions have been tested in a nerve model and found correct. Given this elaboration, and the stated anatomical propositions, existing knowledge of interaction provides an adequate theoretical basis for an elementary understanding of dorsal root potentials. The study of general properties and the analysis of dorsal root potentials have led to the formulation of certain conclusions that follow. D.R.I, II, and III record the electrotonic spread of polarization resulting from the external field of impulses conducted in the intramedullary segment and longitudinal trajects of primary afferent fibers. D.R.IV arises in part as the result of activity in primary afferent fibers, and in part as the result of activity in secondary neurons. In either case the mode of production is the same, and the responsible agent is residual negativity in the active collaterals, or, more precisely, the external field of current flow about the collaterals during the period of residual negativity. Current flow about active primary afferent collaterals during the period of residual negativity is the agent for residual facilitation of monosynaptic reflex pathways. Since the changes in reflex threshold follow the course of residual negativity there is no need to postulate especial properties for prolonging action at regions the threshold of which is measured by means of monosynaptic test reflexes. D.R.V results from polarization of primary afferent fibers by current flow about secondary neurons. There is indication that somata rather than axons of secondary neurons generate the polarizing currents. Similarity between D.R.V and the positive intermediary potential further indicates that soma gradients established during the recovery cycle are responsible for D.R.V. Little or no net polarization of primary afferent fibers results from activity confined to the contralateral gray substance, the dorsal root potentials in contralateral recording resulting from interaction in the dorsal column or in the ipsilateral gray substance following decussation of contralaterally evoked activity. During the course of asphyxia the initial defect in reflex pathways is the failure of secondary neurons to respond to primary impulses. Subsequently block is established at the branching zone of primary afferent fibers. A relation exists between the sequence of dorsal root potentials and the cord potential sequence, the major departure from exact correspondence occurring in the region of D.R.IV and the negative intermediary potential and being of a nature to suggest that different aspects of internuncial activity are emphasized by the two methods of leading.

Lloyd, David P. C.; McIntyre, A. K.

1949-01-01

264

Optimization and Implementation of Long Nerve Allografts.  

National Technical Information Service (NTIS)

Loss of nerve function occurs when a nerve is severed. Any significant loss of nerve tissue requires a graft to restore continuity and promote nerve regeneration and recovery of function. Presently, there is no acceptable nerve grafting method for the rep...

D. F. Muir

2013-01-01

265

Peripheral nerve injuries in children.  

PubMed

Recovery after peripheral nerve injuries in children is more complete than in adults and is inversely related to the age of the patient. The prognosis for the return of sensation following laceration of the median, ulnar, or digital nerve depends upon recovery of two point discrimination (in millimeters approximately equal to the child's age) at the time of nerve repair. The better results in children probably reflect the greater adaptability of the immature central nervous system to the nerve injury. Operative exploration of an open wound when there is a potential for nerve injury in an uncooperative child is the only sure way of determining the status of the nerves. Primary repair of cleanly divided nerves in tidy wounds is advocated if it can be done competently. Secondary repair is indicated for avulsion injuries, gunshot wounds, crush injuries, and human or animal bites. Delicate, atraumatic technique and accurate repair of the divided nerve are stressed. The more exacting technique of funicular repair may yield better results. Interfascicular cable grafting is a new and useful alternative to extensive mobilization in closing nerve gaps. Nonoperative treatment of nerve injuries associated with closed fractures is advocated unless there are no signs of nerve regeneration in two to three months. Obstetrical brachial plexus injuries of the upper plexus carry a better prognosis than lower plexus or total plexus injury. Early range of motion exercises to prevent contractures are stressed. Maximal recovery takes place within two years. The acute nerve compression syndrome should be considered an emergency and may require surgical decompression if it is severe and if rapid return of function does not occur following reduction of the fracture. PMID:958691

Frykman, G K

1976-07-01

266

Fibrolipoma of the median nerve.  

PubMed

Neural fibrolipoma or fibrolipomatous hamartoma is an uncommon benign tumor that usually arises in the median nerve. Fibrofatty tissue proliferates around the nerve and infiltrates the epineurium and perineurium. We report a case of fibrolipomatous hamartoma of the left median nerve in an 18-year-old woman. Our objective was to describe the pathognomonic magnetic resonance imaging features, whose presence obviates the need for a diagnostic biopsy. PMID:17178460

Nouira, Kais; Belhiba, Hend; Baccar, Sofiène; Miaaoui, Anissa; Ben Messaoud, Monia; Turki, Imène; Cheour, Ilhem; Menif, Emna

2007-01-01

267

40 CFR 205.153 - Engine displacement.  

Code of Federal Regulations, 2013 CFR

...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.153 Engine displacement. (a) Engine displacement must be calculated using nominal engine values and...

2013-07-01

268

Fixture for Linearly Variable Displacement Transducers  

NASA Technical Reports Server (NTRS)

Original point of interest on shear panel tracked throughout loading. Technique and fixture measure out-of-plane displacements on shear panel using linearly variable displacement transducers (LVDT's) while tracking original panel location. Technique adaptable to any size shear panel.

Farley, G. L.; Baker, D. J.

1985-01-01

269

High division of the spinal accessory nerve and communication with a C2 branch of the cervical plexus: a previously unreported anatomical variant.  

PubMed

Anatomical variations of the spinal accessory nerve are well known. We describe a previously unreported variant in which the nerve divided high in level II after crossing the internal jugular vein and before entering the sternomastoid muscle. Both branches were joined by a communication from the C2 cervical root. We discuss the clinical implications of this finding. PMID:24792860

Matthews, L A; Blythe, J N; Brennan, P A

2014-07-01

270

Displacement Compensation of Temperature Probe Data  

NASA Technical Reports Server (NTRS)

Analysis of temperature data from a probe in a vertical Bridgman furnace growing germanium crystals revealed a displacement of the temperature profile due to conduction error. A theoretical analysis shows that the displacement compensation is independent of local temperature gradient. A displacement compensation value should become a standard characteristic of temperature probes used for temperature profile measurements.

Welch, Christopher S.; Hubert, James A.; Barber, Patrick G.

1996-01-01

271

Nerve-pulse interactions  

SciTech Connect

Some recent experimental and theoretical results on mechanisms through which individual nerve pulses can interact are reviewed. Three modes of interactions are considered: (1) interaction of pulses as they travel along a single fiber which leads to velocity dispersion; (2) propagation of pairs of pulses through a branching region leading to quantum pulse code transformations; and (3) interaction of pulses on parallel fibers through which they may form a pulse assembly. This notion is analogous to Hebb's concept of a cell assembly, but on a lower level of the neural hierarchy.

Scott, A.C.

1982-01-01

272

Magnetic-motor-root stimulation: review.  

PubMed

Magnetic stimulation can activate the human central and peripheral nervous systems non-invasively and virtually painlessly. Magnetic stimulation over the spinal enlargements can activate spinal nerves at the neuroforamina (magnetic-neuroforamina stimulation). This stimulation method provides us with information related to the latency of compound-muscle action potential (CMAP), which is usually interpreted as peripheral motor-conduction time (PMCT). However, this stimulation method has faced several problems in clinical applications. One is that supramaximal CMAPs were unobtainable. Another is that magnetic stimulation did not usually activate the spinal nerves in the spinal canal, i.e., the cauda equina, which prevented an evaluation of its conduction. For these reasons, magnetic-neuroforamina stimulation was rarely used to evaluate the conduction of peripheral nerves. It was mainly used to evaluate the conduction of the corticospinal tract using the parameter of central motor-conduction time (CMCT), which was calculated by subtracting PMCT from the latency of motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) over the primary motor cortex. Recently, supramaximal stimulation has been achieved in magnetic-neuroforamina stimulation, and this has contributed to the measurement of both CMAP size and latency. The achievement of supramaximal stimulation is ascribed to the increase in magnetic-stimulator output and a novel coil, the magnetic augmented translumbosacral stimulation (MATS) coil. The most proximal part of the cauda equina can be reliably activated using the MATS coil (magnetic-conus stimulation), thus contributing to the measurement of cauda equina conduction time (CECT) and cortico-conus motor-conduction time (CCCT). These recent developments in magnetic-motor-root stimulation enable us to more precisely evaluate the conduction of the proximal part of peripheral nerves and that of the corticospinal tract for lower-limb muscles. In this review article, we summarise the basic mechanisms, recent topics, clinical applications, comparison to electrical stimulation, pitfalls, safety and additional issues in magnetic-motor-root stimulation. PMID:23485367

Matsumoto, Hideyuki; Hanajima, Ritsuko; Terao, Yasuo; Ugawa, Yoshikazu

2013-06-01

273

Patterns of slow transport in sensory nerves  

SciTech Connect

An examination of the pattern of outflow of radioactivity in sciatic nerves was made at times from 1 to 82 days in the rat and up to 132 days in the cat after injecting the L5 and L7 dorsal root ganglia, respectively, with 3H-leucine. Slow waves moving at a rate of 1-2 mm/day were looked for on the basis of their reported presence in the motor fibers of the rat. A consistent pattern of slow waves was not seen in the cat or rat sensory fibers of the sciatic nerves nor was evidence of a slow wave found in the cat dorsal columns. Irregularities in the pattern of outflow which at times appeared as waves did so in an irregular fashion, a pattern inconsistent with a steady progression of slow waves in the fibers. The decrease of radioactivity appearing first near the ganglia helps create the impression of a wave along with irregular decreases in the overall levels of radio-activity with time. The results were explained on the basis of the unitary hypothesis. The labeled components are considered to be moved down the fiber by the fast transport mechanism, those components dropping off locally in the fibers early on, constituting the slow wave. As those components turn over locally in the various organelles of fiber and are further redistributed, they may at times give rise to what appears as waves.

Stromska, D.P.; Ochs, S.

1981-09-01

274

Managing Chemotherapy Side Effects: Nerve Changes  

MedlinePLUS

... national institutes of health Managing Chemotherapy Side Effects Nerve Changes “My fingers and toes felt numb and ... from getting cuts, I always wore shoes.” About nerve changes Some chemotherapy can cause nerve problems. You ...

275

Spectral properties of displacement models  

NASA Astrophysics Data System (ADS)

The recent study of Schrodinger operators with random potentials has provided significant insight into our understanding of the electronic properties of disordered media. This work presents new results concerning the spectrum of a class of random operators called displacement models. Such models may be used to model solids in which the positions of the individual atoms are randomly perturbed from an ideal periodic lattice. In particular, we will provide a characterization of the almost sure spectral minimum of the random displacement model, bounds on the integrated density of states, and a rigourous proof of the lack of classical Lifshitz tails under suitable assumptions on the random parameters. The fundamental tool used throughout the work is a quite general phenomenon in the spectral theory of Neumann problems, which we dub "bubbles tend to the boundary." How should a given compactly supported potential be placed into a bounded domain so as to minimize or maximize the first Neumann eigenvalue of the Schrdinger operator on this domain? For square or rectangular domains and reflection symmetric potentials, we show that the first Neumann eigenvalue is minimized when the potential sits in one of the corners of the domain and is maximized when it sits in the center of the domain. With different methods we also show a corresponding result for smooth strictly convex domains.

Baker, Steven

276

Interferometric fiber optic displacement sensor  

DOEpatents

A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 23 figs.

Farah, J.

1999-04-06

277

Interferometric fiber optic displacement sensor  

SciTech Connect

A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 29 figs.

Farah, J.

1995-05-30

278

Interferometric fiber optic displacement sensor  

DOEpatents

A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically.

Farah, John (M.I.T. P.O. Box 397301, Cambridge, MA 02139)

1999-01-01

279

Interferometric fiber optic displacement sensor  

DOEpatents

A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically.

Farah, John (M.I.T. Branch P.O. Box 301, Cambridge, MA 02139)

1995-01-01

280

Modeling the Effects of Strain During Progressive Failure of Root-Reinforced Soils  

NASA Astrophysics Data System (ADS)

It is widely recognized that plant root systems act to reinforce a mass of soil against shear failure. Simple perpendicular root models evaluate root-reinforcement as an additional soil shear strength term, but assume that the full tensile strength of each root is mobilized during soil shearing and that the roots all break simultaneously. Much of the resulting overestimation was reduced by employing a Fiber-Bundle Model (FBM) to simulate progressive root breakage. Further improvements can be made by evaluating a term accounting for initial root orientation, shear distortion angle and soil friction angle for each root. As individual root orientations are often unknown, a Monte Carlo approach has been successfully used to simulate plants with heartroot, plateroot and taproot/herringbone networks growing on slopes and floodplains. However, the effect of root extension (strain) has been ignored to date. Herein, we extend the Monte Carlo framework to incorporate root extension during loading and investigate its impact on both the spatio-temporal dynamics of soil-root systems during failure and the magnitude of soil shear strength reinforcement. Time-dependence is introduced by coupling equations describing the geometry of each root crossing a potential failure plane with equations describing the motion of the failure block. Simulation results indicate that root architecture has a significant impact on loading curve shape and the peak load supported by a root bundle. The duration and displacement over which reinforcement is provided are controlled by the proportions of compressed and tensioned roots as soil shearing initiates.

Thomas, R. E.; Bankhead, N. L.

2009-12-01

281

Biodegradable fibrin conduit promotes long-term regeneration after peripheral nerve injury in adult rats.  

PubMed

Peripheral nerve injuries are often associated with loss of nerve tissue and require autologous nerve grafts to provide a physical substrate for axonal growth. Biosynthetic neural conduits could be an alternative treatment strategy in such injuries. The present study investigates the long-term effects of a tubular fibrin conduit on neuronal regeneration, axonal sprouting and recovery of muscle weight following peripheral nerve injury and repair in adult rats. Sciatic axotomy was performed proximally in the thigh to create a 10-mm gap between the nerve stumps. The injury gap was bridged by using a 14-mm-long fibrin glue conduit, entubulating 2 mm of the nerve stump at each end. A reversed autologous nerve graft was used as a control. The regenerative response from sensory and motor neurones was evaluated following retrograde labelling with Fast Blue fluorescent tracer. In control experiments, at 16 weeks following peripheral nerve grafting, 5184 (±574 standard error of mean (SEM)) sensory dorsal root ganglion neurones and 1001 (±37 SEM) spinal motor neurones regenerated across the distal nerve-graft interface. The fibrin conduit promoted regeneration of 60% of sensory neurones and 52% of motor neurones when compared to the control group. The total number of myelinated axons in the distal nerve stump in the fibrin-conduit group reached 86% of the control and the weight of gastrocnemius and soleus muscles recovered to 82% and 89% of the controls, respectively. The present results suggest that a tubular fibrin conduit can be used to promote neuronal regeneration following peripheral nerve injury. PMID:20005193

Pettersson, Jonas; Kalbermatten, Daniel; McGrath, Aleksandra; Novikova, Liudmila N

2010-11-01

282

Nerve Agent Sensing Biopolymer Wipe.  

National Technical Information Service (NTIS)

This research and development project entitled 'Nerve Agent Sensing Biopolymer Wipe' is directed at developing a simple-to-use enzyme-containing sensor for detecting nerve agent contamination at surfaces, in air and in solution, and to provide a tool for ...

M. Erbeldinger K. LeJeune

2003-01-01

283

Functions of the Renal Nerves.  

ERIC Educational Resources Information Center

Discusses renal neuroanatomy, renal vasculature, renal tubules, renin secretion, renorenal reflexes, and hypertension as related to renal nerve functions. Indicates that high intensitites of renal nerve stimulation have produced alterations in several renal functions. (A chart with various stimulations and resultant renal functions and 10-item,…

Koepke, John P.; DiBona, Gerald F.

1985-01-01

284

Nerve welding by Ar+ laser  

NASA Astrophysics Data System (ADS)

The comparative study of sciatic nerve microepincutral anastomoses with Ar+ laser and conventional suture techniques was made on rats. Total tests included electrophysiological and histopathological studies. The result of the experiment showed that nerve welding with laser is better than conventional suture techniques.

Wei, Dong-Ji; Li, Xiao-Yuan; Zhang, Ai-Hua; Deng, Zue-Xing; Xu, Gue-Xiang

1998-11-01

285

Reinforcement of Tree Root and Non-frame Method in Slope Stabilization  

NASA Astrophysics Data System (ADS)

A root fiber can nail a slipping soil mass into the bedrock and thus can increase slope stability. The reinforcement of root fibers is considered as the resultant of tension and shear reinforces occurred in the cross section of root at slip surface. The shear force and bending moment of a deformed root directly prevent against the displacement of unstable soil mass while the tension force increase the friction force between unstable soil and bed rock. Longer displacement of slope causes larger deformation and thus causes larger reinforcement of tree root. In other side, larger root reinforcement results in more slope stability. The reinforcement of tree root and displacement of slipping soil mass depending on each other is the reinforcement mechanism of tree root in a landslide. The mechanism of tree root reinforcement is considered in developing a new soil nail method named Non-frame. By conducting a number of experiments of soil nail stabilizing slope, the alteration process of root reinforcement was performed in various conditions of rainfall and earthquake.

Naoto, I.; Quang, N. Minh

2009-04-01

286

Nerve glue for upper extremity reconstruction.  

PubMed

Nerve glue is an attractive alternative to sutures to improve the results of nerve repair. Improved axon alignment, reduced scar and inflammation, greater and faster reinnervation, and better functional results have been reported with the use of nerve glue. The different types of nerve glue and the evidence to support or oppose their use are reviewed. Although the ideal nerve glue has yet to be developed, fibrin sealants can be used as nerve glue in select clinical situations. Technology to allow suture-free nerve repair is one development that can potentially improve functional nerve recovery and the outcomes of upper extremity reconstruction. PMID:23101603

Tse, Raymond; Ko, Jason H

2012-11-01

287

Peripheral nerve injury and repair.  

PubMed

Peripheral nerve injuries are common, and there is no easily available formula for successful treatment. Incomplete injuries are most frequent. Seddon classified nerve injuries into three categories: neurapraxia, axonotmesis, and neurotmesis. After complete axonal transection, the neuron undergoes a number of degenerative processes, followed by attempts at regeneration. A distal growth cone seeks out connections with the degenerated distal fiber. The current surgical standard is epineurial repair with nylon suture. To span gaps that primary repair cannot bridge without excessive tension, nerve-cable interfascicular auto-grafts are employed. Unfortunately, results of nerve repair to date have been no better than fair, with only 50% of patients regaining useful function. There is much ongoing research regarding pharmacologic agents, immune system modulators, enhancing factors, and entubulation chambers. Clinically applicable developments from these investigations will continue to improve the results of treatment of nerve injuries. PMID:10951113

Lee, S K; Wolfe, S W

2000-01-01

288

Pulsed Radiofrequency of Lumbar Dorsal Root Ganglion for Chronic Postamputation Phantom Pain  

PubMed Central

Chronic pain following lower-limb amputation is now a well-known neuropathic, chronic-pain syndrome that usually presents as a combination of phantom and stump pain. Controlling these types of neuropathic pain is always complicated and challenging. If pharmacotherapy does not control the patient’s pain, interventional procedures have to be taken. The aim of this study was to evaluate the efficacy of using pulsed radiofrequency (PRF) on the dorsal root ganglia at the L4 and L5 nerve roots to improve phantom pain. Two patients with phantom pain were selected for the study. After a positive response to segmental nerve blockade at the L4 and L5 nerve roots, PRF was performed on the L4 and L5 dorsal root ganglia. Global clinical improvement was good in one patient, with a 40% decrease in pain on the visual analogue scale (VAS) in 6 months, and moderate in the second patient, with a 30% decrease in pain scores in 4 months. PRF of the dorsal root ganglia at the L4 and L5 nerve roots may be an effective therapeutic option for patients with refractory phantom pain.

Imani, Farnad; Gharaei, Helen; Rezvani, Mehran

2012-01-01

289

Intracranial stimulation of the trigeminal nerve in man. III. Sensory potentials  

Microsoft Academic Search

Percutaneous electrical stimulation of the trigeminal root was performed in 18 subjects undergoing surgery for idiopathic trigeminal neuralgia or implantation of electrodes into Meckel's cave for recording of limbic epileptic activity. All subjects had normal trigeminal reflexes and evoked potentials. Sensory action potentials were recorded antidromically from the supraorbital (V1), infraorbital (V2) and mental (V3) nerves. In the awake subject,

G Cruccu; M Inghilleri; M Manfredi; M Meglio

1987-01-01

290

The Root Pressure Phenomenon  

ERIC Educational Resources Information Center

Describes experiments demonstrating that root pressure in plants is probably controlled by a circadian rhythm (biological clock). Root pressure phenomenon plays significant part in water transport in contradiction with prevalent belief. (PS)

Marsh, A. R.

1972-01-01

291

Short root anomaly.  

PubMed

A case of generalised short root anomaly is described. All permanent teeth had abnormally short roots, associated with microdontia, hypodontia and a dens invaginatus. Members of the patient's family were similarly affected. PMID:2261278

Edwards, D M; Roberts, G J

1990-11-10

292

Variable delivery, fixed displacement pump  

DOEpatents

A variable delivery, fixed displacement pump comprises a plurality of pistons reciprocated within corresponding cylinders in a cylinder block. The pistons are reciprocated by rotation of a fixed angle swash plate connected to the pistons. The pistons and cylinders cooperate to define a plurality of fluid compression chambers each have a delivery outlet. A vent port is provided from each fluid compression chamber to vent fluid therefrom during at least a portion of the reciprocal stroke of the piston. Each piston and cylinder combination cooperates to close the associated vent port during another portion of the reciprocal stroke so that fluid is then pumped through the associated delivery outlet. The delivery rate of the pump is varied by adjusting the axial position of the swash plate relative to the cylinder block, which varies the duration of the piston stroke during which the vent port is closed.

Sommars, Mark F. (Sparland, IL)

2001-01-01

293

An ion displacement membrame model.  

PubMed

The usual assumption in treating the diffusion of ions in an electric field has been that the movement of each ion is independent of the movement of the others. The resulting equation for diffusion by a succession of spontaneous jumps has been well stated by Parlin and Eyring. This paper will consider one simple case in which a different assumption is reasonable. Diffusion of monovalent positive ions is considered as a series of jumps from one fixed negative site to another. The sites are assumed to be full (electrical neutrality). Interaction occurs by the displacement of one ion by another. An ion leaves a site if and only if another ion, not necessarily of the same species, attempts to occupy the same site. Flux ratios and net fluxes are given as functions of the electrical potential, concentration ratios, and number of sites encountered in crossing the membrane. Quantitative comparisons with observations of Hodgkin and Keynes are presented. PMID:6048876

Hladky, S B; Harris, J D

1967-09-01

294

Displaced electrode process for welding  

SciTech Connect

A method is described for the butt-welding of a relatively heavy mass to a relatively small mass such as a thin-wall tube. In butt-welding heat is normally applied at the joint between the two pieces which are butt-welded together. The application of heat at the joint results in overheating the tube which causes thinning of the tube walls and porosity in the tube material. This is eliminated by displacing the welding electrode away from the seam toward the heavier mass so that heat is applied to the heavy mass and not at the butt seam. Examples of the parameters used in welding fuel rods are given. The cladding and end plugs were made of Zircalloy. The electrode used was of 2 percent thoriated tungsten. (auth)

Heichel, L.J.

1975-08-26

295

Mapping sensory nerve communications between peripheral nerve territories.  

PubMed

The human cutaneous sensory map has been a work in progress over the past century, depicting sensory territories supplied by both the spinal and cranial nerves. Two critical discoveries, which shaped our understanding of cutaneous innervation, were sensory dermatome overlap between contiguous spinal levels and axial lines across areas where no sensory overlap exists. These concepts define current dermatome maps. We wondered whether the overlap between contiguous sensory territories was even tighter: if neural communications were present in the peripheral nerve territories consistently connecting contiguous spinal levels? A literature search using peer-reviewed articles and established anatomy texts was performed aimed at identifying the presence of communications between sensory nerves in peripheral nerve territories and their relationship to areas of adjacent and non-adjacent spinal or cranial nerves and axial lines (lines of discontinuity) in the upper and lower limbs, trunk and perineum, and head and neck regions. Our findings demonstrate the consistent presence of sensory nerve communications between peripheral nerve territories derived from spinal nerves within areas of axial lines in the upper and lower limbs, trunk and perineum, and head and neck. We did not find examples of communications crossing axial lines in the limbs or lines of discontinuity in the face, but did find examples crossing axial lines in the trunk and perineum. Sensory nerve communications are common. They unify concepts of cutaneous innervation territories and their boundaries, and refine our understanding of the sensory map of the human skin. Clin. Anat. 27:681-690, 2014. © 2013 Wiley Periodicals, Inc. PMID:23824984

Ladak, Adil; Tubbs, R Shane; Spinner, Robert J

2014-07-01

296

Photofabricated gelatin-based nerve conduits: nerve tissue regeneration potentials.  

PubMed

There is a strong demand for development of nerve guide conduit with prompt nerve regeneration potential for injury-induced nerve defect. Prior to study on nerve tissue engineering using Schwann cells or nerve stem cells, the effectiveness of photofabricated scaffolds based on photocurable gelatin was examined. This study describes the evaluation of in vivo nerve tissue regeneration potentials of three custom-designed and -fabricated prostheses (inner diameter, 1.2 mm; outer diameter, 2.4 mm; wall thickness, 0.60 mm; and length, 15 mm) made of photocured gelatin: a plain photocured gelatin tube (model I), a photocured gelatin tube packed with bioactive substances (laminin, fibronectin, and nerve growth factor) coimmobilized in a photocured gelatin rod (model II), and a photocured gelatin tube packed with bioactive substances coimmobilized in multifilament fibers (model III). These prostheses were implanted between the proximal and distal stumps 10 mm of the dissected right sciatic nerve of 70 adult male Lewis rats for up to 1 year. The highest regenerative potentials were found using the model III prosthesis, followed by the model II prosthesis. Markedly retarded neural regeneration was observed using the model I prosthesis. These were evaluated from the viewpoints of functional recovery, electrophysiological responses, and tissue morphological regeneration. The significance of the synergistic cooperative functions of multifilaments, which serve as a platform that provides contact guidance to direct longitudinal cell movement and tissue ingrowth and as a cell adhesive matrix with high surface area, and immobilized bioactive substances, which enhance nerve regeneration via biological stimulation, is discussed. PMID:15565867

Gámez, Eduardo; Goto, Yoshinobu; Nagata, Kengo; Iwaki, Toru; Sasaki, Tomio; Matsuda, Takehisa

2004-01-01

297

Recent advances in nerve tissue engineering.  

PubMed

Nerve injury secondary to trauma, neurological disease or tumor excision presents a challenge for surgical reconstruction. Current practice for nerve repair involves autologous nerve transplantation, which is associated with significant donor-site morbidity and other complications. Previously artificial nerve conduits made from polycaprolactone, polyglycolic acid and collagen were approved by the FDA (USA) for nerve repair. More recently, there have been significant advances in nerve conduit design that better address the requirements of nerve regrowth. Innovations in materials science, nanotechnology, and biology open the way for the synthesis of new generation nerve repair conduits that address issues currently faced in nerve repair and regeneration. This review discusses recent innovations in this area, including the use of nanotechnology to improve the design of nerve conduits and to enhance nerve regeneration. PMID:24811182

Zhang, Bill G X; Quigley, Anita F; Myers, Damian E; Wallace, Gordon G; Kapsa, Robert M I; Choong, Peter F M

2014-05-01

298

Expression of neurotrophic factors in the dorsal root ganglion in a rat model of lumbar disc herniation  

Microsoft Academic Search

A variety of molecules released by inflammatory reactions in the dorsal root and dorsal root ganglion (DRG) may play important roles in the pathology of neuronal abnormalities in lumbar disc herniation. In order to elucidate the pathophysiological mechanisms of painful radiculopathy, secondary to lumbar disc herniation, we evaluated pain-related behavior and the change of nerve growth factor (NGF) and brain-derived

Koichi Obata; Hiroaki Tsujino; Hiroki Yamanaka; Dai Yi; Tetsuo Fukuoka; Norio Hashimoto; Kazuo Yonenobu; Hideki Yoshikawa; Koichi Noguchi

2002-01-01

299

Endoscopic supraorbital nerve neurolysis.  

PubMed

Endoscopic surgery, performed through small incisions, yields therapeutic results equivalent or superior to those obtained using the conventional approach. The technique has been established in laparoscopic cholecystectomic surgery. In plastic surgery, endoscopic techniques were first developed in aesthetic procedures and have been reported to be useful in face-lift operations, breast reconstruction, muscle flap harvesting and subcutaneous surgery. Endobrow lift has become a more and more popular aesthetic procedure. The endoscope provides an excellent magnification and, through a high power light source, a very good illumination of the operative field. It explains why the endoscope is more and more used in reconstructive procedures. We report the case of a patient suffering from a posttraumatic entrapment of the right supraorbital nerve which was released by an endoscopic approach. PMID:10499392

Adant, J P; Bluth, F

1999-08-01

300

Rooting gene trees without outgroups: EP rooting.  

PubMed

Gene sequences are routinely used to determine the topologies of unrooted phylogenetic trees, but many of the most important questions in evolution require knowing both the topologies and the roots of trees. However, general algorithms for calculating rooted trees from gene and genomic sequences in the absence of gene paralogs are few. Using the principles of evolutionary parsimony (EP) (Lake JA. 1987a. A rate-independent technique for analysis of nucleic acid sequences: evolutionary parsimony. Mol Biol Evol. 4:167-181) and its extensions (Cavender, J. 1989. Mechanized derivation of linear invariants. Mol Biol Evol. 6:301-316; Nguyen T, Speed TP. 1992. A derivation of all linear invariants for a nonbalanced transversion model. J Mol Evol. 35:60-76), we explicitly enumerate all linear invariants that solely contain rooting information and derive algorithms for rooting gene trees directly from gene and genomic sequences. These new EP linear rooting invariants allow one to determine rooted trees, even in the complete absence of outgroups and gene paralogs. EP rooting invariants are explicitly derived for three taxon trees, and rules for their extension to four or more taxa are provided. The method is demonstrated using 18S ribosomal DNA to illustrate how the new animal phylogeny (Aguinaldo AMA et al. 1997. Evidence for a clade of nematodes, arthropods, and other moulting animals. Nature 387:489-493; Lake JA. 1990. Origin of the metazoa. Proc Natl Acad Sci USA 87:763-766) may be rooted directly from sequences, even when they are short and paralogs are unavailable. These results are consistent with the current root (Philippe H et al. 2011. Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature 470:255-260). PMID:22593551

Sinsheimer, Janet S; Little, Roderick J A; Lake, James A

2012-01-01

301

Rooting Gene Trees without Outgroups: EP Rooting  

PubMed Central

Gene sequences are routinely used to determine the topologies of unrooted phylogenetic trees, but many of the most important questions in evolution require knowing both the topologies and the roots of trees. However, general algorithms for calculating rooted trees from gene and genomic sequences in the absence of gene paralogs are few. Using the principles of evolutionary parsimony (EP) (Lake JA. 1987a. A rate-independent technique for analysis of nucleic acid sequences: evolutionary parsimony. Mol Biol Evol. 4:167–181) and its extensions (Cavender, J. 1989. Mechanized derivation of linear invariants. Mol Biol Evol. 6:301–316; Nguyen T, Speed TP. 1992. A derivation of all linear invariants for a nonbalanced transversion model. J Mol Evol. 35:60–76), we explicitly enumerate all linear invariants that solely contain rooting information and derive algorithms for rooting gene trees directly from gene and genomic sequences. These new EP linear rooting invariants allow one to determine rooted trees, even in the complete absence of outgroups and gene paralogs. EP rooting invariants are explicitly derived for three taxon trees, and rules for their extension to four or more taxa are provided. The method is demonstrated using 18S ribosomal DNA to illustrate how the new animal phylogeny (Aguinaldo AMA et al. 1997. Evidence for a clade of nematodes, arthropods, and other moulting animals. Nature 387:489–493; Lake JA. 1990. Origin of the metazoa. Proc Natl Acad Sci USA 87:763–766) may be rooted directly from sequences, even when they are short and paralogs are unavailable. These results are consistent with the current root (Philippe H et al. 2011. Acoelomorph flatworms are deuterostomes related to Xenoturbella. Nature 470:255–260).

Sinsheimer, Janet S.; Little, Roderick J. A.; Lake, James A.

2012-01-01

302

Intraneural ganglion cyst on the external popliteal nerve.  

PubMed

There are many causes for the paralysis of the external sciatic popliteal nerve , such as the intraneural ganglion cyst. In this case, we evaluate a 52-year-old woman with no relevant personal record, who was admitted with paresis of the right foot of 4?months of evolution associated with alterations in the sensitivity that rose up to the posterolateral region of the leg. The diagnosis was based on MR and cyst decompression and disconnection of the articular branch. Given the low incidence of these lesions, their origin is still subject to controversy. The most widely accepted theory is the unifying articular theory described by Spinner in the year 2003. Intraneural ganglion cysts must be included in the differential diagnosis of progressive paralysis of the sciatic nerve, lesions of the nerve root at L5 and nerve sheath tumours that start at the lateral compartment of the knee. The treatment of a fibular intraneural ganglion cyst must be surgical and the operation must be performed as soon as possible. PMID:24891476

Rendon, Diego; Pescador, David; Cano, Carlos; Blanco, Juan

2014-01-01

303

Olfactory ensheathing cells seeded muscle-stuffed vein as nerve conduit for peripheral nerve repair: A nerve conduction study.  

PubMed

We evaluated bridging of 15 mm nerve gap in rat sciatic nerve injury model with muscle-stuffed vein seeded with olfactory ensheathing cells as a substitute for nerve autograft. Neurophysiological recovery, as assessed by electrophysiological analysis was faster in the constructed biological nerve conduit compared to that of autograft. PMID:24598302

Lokanathan, Yogeswaran; Ng, Min-Hwei; Hasan, Shariful; Ali, Anuar; Mahmod, Mazzre; Htwe, Ohnmar; Roohi, Sharifah Ahmad; Bt Hj Idrus, Ruszymah; Abdullah, Shalimar; Naicker, Amaramalar Selvi

2014-08-01

304

Materials for peripheral nerve regeneration.  

PubMed

Recent efforts in scientific research in the field of peripheral nerve regeneration have been directed towards the development of artificial nerve guides. We have studied various materials with the aim of obtaining a biocompatible and biodegradable two layer guide for nerve repair. The candidate materials for use as an external layer for the nerve guides were poly(caprolactone) (PCL), a biosynthetic blend between PCL and chitosan (CS) and a synthesised poly(ester-urethane) (PU). Blending PCL, which is a biocompatible synthetic polymer, with a natural polymer enhanced the system biocompatibility and biomimetics, fastened the degradation rates and reduced the production costs. Various novel block poly(ester-urethane)s are being synthesised by our group with tailored properties for specific tissue engineering applications. One of these poly(ester-urethane)s, based on a low molecular weight poly(caprolactone) as the macrodiol, cycloesandimethanol as the chain extender and hexamethylene diisocyanate as the chain linker, was investigated for the production of melt extruded nerve guides. We studied natural polymers such as gelatin (G), poly(L-lysine) (PL) and blends between chitosan and gelatin (CS/G) as internal coatings for nerve guides. In vitro and in vivo tests were performed on PCL guides internally coated either with G or PL to determine the differences in the quality of nerve regeneration associated with the type of adhesion protein. CS/G natural blends combined the good cell adhesion properties of the protein phase with the ability to promote nerve regeneration of the polysaccharide phase. Natural blends were crosslinked both by physical and chemical crosslinking methods. In vitro neuroblast adhesion tests were performed on CS/G film samples, PCL/CS and PU guides internally coated with G to evaluate the ability of such materials towards nerve repair. PMID:16374766

Ciardelli, Gianluca; Chiono, Valeria

2006-01-01

305

Comparison of hemihypoglossal-facial nerve transposition with a cross-facial nerve graft and muscle transplant for the rehabilitation of facial paralysis using the facial clima method.  

PubMed

To compare quantitatively the results obtained after hemihypoglossal nerve transposition and microvascular gracilis transfer associated with a cross facial nerve graft (CFNG) for reanimation of a paralysed face, 66 patients underwent hemihypoglossal transposition (n = 25) or microvascular gracilis transfer and CFNG (n = 41). The commissural displacement (CD) and commissural contraction velocity (CCV) in the two groups were compared using the system known as Facial clima. There was no inter-group variability between the groups (p > 0.10) in either variable. However, intra-group variability was detected between the affected and healthy side in the transposition group (p = 0.036 and p = 0.017, respectively). The transfer group had greater symmetry in displacement of the commissure (CD) and commissural contraction velocity (CCV) than the transposition group and patients were more satisfied. However, the transposition group had correct symmetry at rest but more asymmetry of CCV and CD when smiling. PMID:22455573

Hontanilla, Bernardo; Vila, Antonio

2012-02-01

306

Outcome of axillary nerve injuries treated with nerve grafts.  

PubMed

This study evaluates the outcome of axillary nerve injuries treated with nerve grafting. Thirty-six patients were retrospectively reviewed after a mean of 53 months (minimum 12 months). The mean interval from injury to surgery was 6.5 months. Recovery of deltoid function was assessed by the power of both abduction and retropulsion, the deltoid bulk and extension lag. The deltoid bulk was almost symmetrical in nine of 34 cases, good in 22 and wasted in three. Grade M4 or M5* was achieved in 30 of 35 for abduction and in 32 of 35 for retropulsion. There was an extension lag in four patients. Deltoid bulk continued to improve with a longer follow-up following surgery. Nerve grafting to the axillary nerve is a reliable method of regaining deltoid function when the lesion is distal to its origin from the posterior cord. PMID:21546415

Okazaki, M; Al-Shawi, A; Gschwind, C R; Warwick, D J; Tonkin, M A

2011-09-01

307

Nanofiber Nerve Guide for Peripheral Nerve Repair and Regeneration.  

National Technical Information Service (NTIS)

The primary goal of this collaborative research project is to develop next generation engineered nerve guide conduits (NGCs) with aligned nanofibers and favorable release kinetics of neurotrophic factors to help improve surgical outcomes after injuries in...

A. Hoke H. Mao

2013-01-01

308

COMPETITIVE DISPLACEMENT AMONG INSECTS AND ARACHNIDS  

Microsoft Academic Search

? Abstract Competitive displacement,is the most severe outcome,of interspecific competition. For the purposes of this review, we define this type of displacement as the removal,of a formerly established species from a habitat as a result of direct or indirect competitive,interactions with another species. We reviewed,the literature for recent putative cases of competitive displacement,among,insects and arachnids and assessed the evidence,for the

Stuart R. Reitz; John T. Trumble

2001-01-01

309

An improved displacement damage monitor LED  

Microsoft Academic Search

A frequency-domain technique for measuring carrier lifetime in GaAs light-emitting-diode (LED) displacement damage monitors capable of high sensitivity and repeatability is developed. Applications of this technique that take advantage of the high sensitivity of this method, including the measurement of the threshold energy for lattice displacement in GaAs, are described. The measured minimum electron energy for displacement damage was 270±15

A. L. Barry; R. Maxseiner; R. Wojcik; M. A. Briere; D. Braeunig

1990-01-01

310

Transverse sacral fractures with anterior displacement  

Microsoft Academic Search

Transverse fractures of the sacrum with anterior displacement are the rarest type of transverse sacral fractures. They usually\\u000a occur at the S1–S2 region in suicide jumpers. A clinical study was performed to evaluate the diagnosis, treatment and outcome\\u000a of transverse sacral fractures with anterior displacement. We present six patients with a transverse fracture of the sacrum\\u000a with anterior displacement. All

George S. Sapkas; Andreas F. Mavrogenis; Panayiotis J. Papagelopoulos

2008-01-01

311

Lateral displacement estimation using tissue incompressibility  

Microsoft Academic Search

Using the incompressibility property of soft tissue, lateral displacements can be reconstructed from axial strain measurements. Results of simulations and experiments on gelatin-based tissue equivalent phantoms are compared with theoretical displacements, as well as estimates derived from traditional speckle tracking. Incompressibility processing greatly improves the accuracy and signal-to-noise ratio (SNR) of lateral displacement measurements compared with more traditional speckle tracking

Mark A. Lubinski; Stanislav Y. Emelianov; K. R. Raghavan; Andrew E. Yagle; Andrei R. Skovoroda; Matthew O'Donnell

1996-01-01

312

Sciatic nerve regeneration is not inhibited by anti-NGF antibody treatment in the adult rat.  

PubMed

Elevated nerve growth factor (NGF) is believed to play a role in many types of pain. An NGF-blocking antibody (muMab 911) has been shown to reduce pain and hyperalgesia in pain models, suggesting a novel therapeutic approach for pain management. Since NGF also plays important roles in peripheral nervous system development and sensory nerve outgrowth, we asked whether anti-NGF antibodies would adversely impact peripheral nerve regeneration. Adult rats underwent a unilateral sciatic nerve crush to transect axons and were subcutaneously dosed weekly for 8weeks with muMab 911 or vehicle beginning 1day prior to injury. Plasma levels of muMab 911 were assessed from blood samples and foot print analysis was used to assess functional recovery. At 8-weeks post-nerve injury, sciatic nerves were prepared for light and electron microscopy. In a separate group, Fluro-Gold was injected subcutaneously at the ankle prior to perfusion, and counts and sizes of retrogradely labeled and unlabeled dorsal root ganglion neurons were obtained. There was no difference in the time course of gait recovery in antibody-treated and vehicle-treated animals. The number of myelinated and nonmyelinated axons was the same in the muMab 911-treated crushed nerves and intact nerves, consistent with observed complete recovery. Treatment with muMab 911 did however result in a small decrease in average cell body size on both the intact and injured sides. These results indicate that muMab 911 did not impair functional recovery or nerve regeneration after nerve injury in adult rats. PMID:23531437

Lankford, K L; Arroyo, E J; Liu, C-N; Somps, C J; Zorbas, M A; Shelton, D L; Evans, M G; Hurst, S I; Kocsis, J D

2013-06-25

313

The Study of Diagnostic Efficacy of Nerve Conduction Study Parameters in Cervical Radiculopathy  

PubMed Central

Background: Cervical Radiculopathy (CR) is a neurologic condition characterised by dysfunction of a cervical spinal nerve, the roots of the nerve, or both. Diagnostic criteria for CR are not well defined, and no universally accepted criteria for its diagnosis have been established. Clinical examination, radiological imaging and electrophysiologic evaluation are the different modalities to diagnose CR. The incidence of Cervical Spondylosis and related conditions is increasing in the present scenario and the use of radiologic examination is time consuming and uneconomical for the common Indian setup. Thus, there is a definite need to establish a cost effective, reliable, and accurate means for establishing the diagnosis of cervical radiculopathy. Electrodiagnostic tests are the closest to fulfill these criteria. Aim: To evaluate diagnostic utility of various motor and sensory nerve conduction study parameters in cervical radiculopathy. Setting and Design: It was a cross-sectional study conducted on 100 subjects of age > 40 years. Material and Methods: The consecutive patients clinically diagnosed to have cervical radiculopathy, referred from department of Orthopaedics were prospectively recruited for the motor and sensory nerve conduction study using RMS EMG EP Mark-II. Parameters studied were Compound Muscle Action Potential (CMAP), Distal Motor Latency (DML) and Conduction Velocity (CV) for motor nerves and Sensory Nerve Action Potential (SNAP) and CV for sensory nerves. Statistical Analysis: Study observations and results were analysed to find the Specificity, Sensitivity, Positive Predictive Value and Negative Predictive Value using SPSS 16.0. Results: Among various motor nerve conduction parameters CMAP was found to be more sensitive with high positive predicative value. CV was found to have greater specificity and DML had least negative predictive value. Sensory nerve conduction parameters were found to have less sensitivity but higher specificity as compared to motor parameters. Conclusion: Nerve conduction studies are useful supportive diagnostic tool for suspected cervical radiculopathy as they are found to have reliable sensitivity and specificity.

Pawar, Sachin; Kashikar, Aditi; Shende, Vinod; Waghmare, Satish

2013-01-01

314

Displacement based multilevel structural optimization  

NASA Technical Reports Server (NTRS)

Multidisciplinary design optimization (MDO) is expected to play a major role in the competitive transportation industries of tomorrow, i.e., in the design of aircraft and spacecraft, of high speed trains, boats, and automobiles. All of these vehicles require maximum performance at minimum weight to keep fuel consumption low and conserve resources. Here, MDO can deliver mathematically based design tools to create systems with optimum performance subject to the constraints of disciplines such as structures, aerodynamics, controls, etc. Although some applications of MDO are beginning to surface, the key to a widespread use of this technology lies in the improvement of its efficiency. This aspect is investigated here for the MDO subset of structural optimization, i.e., for the weight minimization of a given structure under size, strength, and displacement constraints. Specifically, finite element based multilevel optimization of structures (here, statically indeterminate trusses and beams for proof of concept) is performed. In the system level optimization, the design variables are the coefficients of assumed displacement functions, and the load unbalance resulting from the solution of the stiffness equations is minimized. Constraints are placed on the deflection amplitudes and the weight of the structure. In the subsystems level optimizations, the weight of each element is minimized under the action of stress constraints, with the cross sectional dimensions as design variables. This approach is expected to prove very efficient, especially for complex structures, since the design task is broken down into a large number of small and efficiently handled subtasks, each with only a small number of variables. This partitioning will also allow for the use of parallel computing, first, by sending the system and subsystems level computations to two different processors, ultimately, by performing all subsystems level optimizations in a massively parallel manner on separate processors. It is expected that the subsystems level optimizations can be further improved through the use of controlled growth, a method which reduces an optimization to a more efficient analysis with only a slight degradation in accuracy. The efficiency of all proposed techniques is being evaluated relative to the performance of the standard single level optimization approach where the complete structure is weight minimized under the action of all given constraints by one processor and to the performance of simultaneous analysis and design which combines analysis and optimization into a single step. It is expected that the present approach can be expanded to include additional structural constraints (buckling, free and forced vibration, etc.) or other disciplines (passive and active controls, aerodynamics, etc.) for true MDO.

Striz, Alfred G.

1995-01-01

315

Cranial nerve injuring during carotid endarterectomy.  

PubMed

Injury to the greater auricular, hypoglossal and superior laryngeal nerves during carotid endarterectomy is preventable. A knowledge of regional anatomy and the mechanisms of such injury allows prevention of this complication. Unilateral individual nerve injury is generally well tolerated, but bilateral or combined nerve injuries can pose a serious threat to life. Minor modifications in technique aid greatly in avoiding nerve injury. PMID:836092

Verta, M J; Applebaum, E L; McClusky, D A; Yao, J S; Bergan, J J

1977-02-01

316

Microbial Adhesion in Flow Displacement Systems  

PubMed Central

Flow displacement systems are superior to many other (static) systems for studying microbial adhesion to surfaces because mass transport and prevailing shear conditions can be adequately controlled and notoriously ill-defined slight rinsing steps to remove so-called “loosely adhering organisms” can be avoided. In this review, we present the basic background required to calculate mass transport and shear rates in flow displacement systems, focusing on the parallel plate flow chamber as an example. Critical features in the design of flow displacement systems are discussed, as well as different strategies for data analysis. Finally, selected examples of working with flow displacement systems are given for diverse biomedical applications.

Busscher, Henk J.; van der Mei, Henny C.

2006-01-01

317

Significance of radiological variables studied on orthopantamogram to pridict post-operative inferior alveoler nerve paresthesia after third molar extraction.  

PubMed

Context: Removal of impacted third molar is a procedure that is often associated with post-operative complications. The rate of complications is somewhat high because of its proximity to the vital structures. Inferior alveolar nerve paresthesia is one of the common complications of impacted their molar surgery. This is due to intimate relationship between roots of mandibular third molar and inferior alveolar canal. To access the proximity of inferior alveolar canal to third molar many diagnostic methods are suggested but in conventional radiography orthopantamogram is considered as the best. There are many findings onorthopantamogram that are suggestive of close proximity of nerve to the canal. In this study authors reviewed seven radiographic findings related to proximity of roots to the inferior alveolar nerve as seen on orthopantamogram and try to find a relationship between these radiographic variables and presence of post-operative paresthesia. Study Design: The study containd 100 impacted third molars need to be removed. Presence of radiographic findings on orthopantamogram were noted and analyzed, to find a relationship with occurrence of post-operative inferior alveolar nerve paresthesia. Materials and Methods: This study comprises of 100 impacted third molar teeth indicated for extraction. Cases were randomly selected from the patients, needs to undergo extraction of impacted mandibular third molar. After extraction cases were evaluated for occurrence of inferior alveolar nerve paresthesia. Stastical Analyisis: Data was transferred to SPss 21 software for frequency calculation, and two tailed p-values were obtained betweens these variables and post-operative paresthesia, by applying Fischer's exact test (GRAPH PAD SOFTWARE). Results: Out of seven, four radiological findings that are grooving of roots, hooked roots, bifid roots and obliteration of white line are significantly related to post-operative paresthesia while bending of canal, narrow canal and darkening of tooth roots over the canal are not significantly associated with post-operative morbidity of facial nerve. PMID:24995248

Pathak, Sachin; Mishra, Nitin; Rastogi, Madhur Kant; Sharma, Shalini

2014-05-01

318

Significance of Radiological Variables Studied on Orthopantamogram to Pridict Post-Operative Inferior Alveoler Nerve Paresthesia After Third Molar Extraction  

PubMed Central

Context: Removal of impacted third molar is a procedure that is often associated with post-operative complications. The rate of complications is somewhat high because of its proximity to the vital structures. Inferior alveolar nerve paresthesia is one of the common complications of impacted their molar surgery. This is due to intimate relationship between roots of mandibular third molar and inferior alveolar canal. To access the proximity of inferior alveolar canal to third molar many diagnostic methods are suggested but in conventional radiography orthopantamogram is considered as the best. There are many findings onorthopantamogram that are suggestive of close proximity of nerve to the canal. In this study authors reviewed seven radiographic findings related to proximity of roots to the inferior alveolar nerve as seen on orthopantamogram and try to find a relationship between these radiographic variables and presence of post-operative paresthesia. Study Design: The study containd 100 impacted third molars need to be removed. Presence of radiographic findings on orthopantamogram were noted and analyzed, to find a relationship with occurrence of post-operative inferior alveolar nerve paresthesia. Materials and Methods: This study comprises of 100 impacted third molar teeth indicated for extraction. Cases were randomly selected from the patients, needs to undergo extraction of impacted mandibular third molar. After extraction cases were evaluated for occurrence of inferior alveolar nerve paresthesia. Stastical Analyisis: Data was transferred to SPss 21 software for frequency calculation, and two tailed p-values were obtained betweens these variables and post-operative paresthesia, by applying Fischer’s exact test (GRAPH PAD SOFTWARE). Results: Out of seven, four radiological findings that are grooving of roots, hooked roots, bifid roots and obliteration of white line are significantly related to post-operative paresthesia while bending of canal, narrow canal and darkening of tooth roots over the canal are not significantly associated with post-operative morbidity of facial nerve.

Mishra, Nitin; Rastogi, Madhur Kant; Sharma, Shalini

2014-01-01

319

A Nerve Cuff Electrode For Controlled Reshaping Of Nerve Geometry  

PubMed Central

The purpose of this study is the development of a nerve electrode that reorganizes nerve geometry slowly and controllably. The Flat Interface Nerve Electrode (FINE) can reshape the nerve into an elongated oval and provide selective stimulation. However, the rate of closure of this electrode is difficult to control. The Slowly Closing – FINE (SC-FINE) is designed with an opening height larger than the size of the nerve to accommodate initial swelling. The electrode closes slowly to reshape the nerve into the desired flat geometry. The SC-FINE is created by combining the reshaping properties of the FINE and the controllable degradation of Poly (DL lactic-co-glycolic) acid (PLGA). Bonding 50/50 or 65/35 PLGA to a stretched FINE increased the opening heights (OH) on average from 0.1 mm to 1.66 ± 0.45 and 2.05 ± 0.55 mm respectively. The addition of the PLGA films controls the time course of closure over a period of 16 ± 1 days and 14 to 16 hours for the 50/50 and 65/35 SC-FINEs respectively in vitro. An in vivo chronic experiment using 50/50 SC-FINEs implanted in 28 rats with an average OH of 1.87 ± 0.34 mm show that the reshaping periods in vivo and in vitro are similar.

Caparso, Anthony V.; Mansour, Joseph M.; Durand, Dominique M.

2013-01-01

320

Construction of tissue engineered nerve grafts and their application in peripheral nerve regeneration  

Microsoft Academic Search

Surgical repair of severe peripheral nerve injuries represents not only a pressing medical need, but also a great clinical challenge. Autologous nerve grafting remains a golden standard for bridging an extended gap in transected nerves. The formidable limitations related to this approach, however, have evoked the development of tissue engineered nerve grafts as a promising alternative to autologous nerve grafts.

Xiaosong Gu; Fei Ding; Yumin Yang; Jie Liu

2011-01-01

321

Peripheral nerve injuries during carotid endarterectomy.  

PubMed

Peripheral nerve injuries associated with carotid endarterectomy are fairly common but not emphasized in reported results of carotid endarterectomy. The sensory nerves to the submandibular skin and ear lobe are often damaged. Motor nerves VII, IX, X, XI and XII may be injured at surgery. The commonest motor injuries involve the facial, vagus and hypoglossal nerves. Carotid endarterectomy was studied prospectively over 1 year to document the incidence of nerve injury. Nerve injury occurred in 12% of patients, with facial and vagus nerves being involved in 4% each. Careful surgical technique based on appropriate anatomical knowledge can prevent most of these complications. PMID:3815175

Downs, A R; Jessen, M; Lye, C R

1987-01-01

322

MicroRNA machinery responds to peripheral nerve lesion in an injury-regulated pattern  

PubMed Central

Recently, functional and potent RNA interference (RNAi) has been reported in peripheral nerve axons transfected with short-interfering RNA (siRNA). In addition, components of RNA-induced silencing complex (RISC) have been identified in axotomized sciatic nerve fibers as well as in regenerating dorsal root ganglia (DRG) neurons in vitro. Based on these observations, and on the fact that siRNA and microRNAs (miRNA) share the same effector enzymes, we hypothesized that the endogenous miRNA biosynthetic pathway would respond to peripheral nerve injury. To answer this question, we investigated changes in the expression of miRNA biosynthetic enzymes following peripheral nerve crush injury in mice. Here we show that several pivotal miRNA biosynthetic enzymes are expressed in an injury-regulated pattern in sciatic nerve in vivo, and in DRG axons in vitro. Moreover, the sciatic nerve lesion induced expression of mRNA-processing bodies (P-bodies), which are the local foci of mRNA degradation in DRG axons. In addition, a group of injury-regulated miRNAs was identified by miRNA microarray and validated by qPCR and in situ hybridization analyses. Taken together, our data support the hypothesis that the peripheral nerve regeneration processes may be regulated by miRNA pathway.

Wu, Di; Raafat, Mohamed; Pak, Elena; Hammond, Scott; Murashov, Alexander K.

2011-01-01

323

Bilateral peripheral neural activity observed in vivo following unilateral nerve injury  

PubMed Central

Manganese-enhanced magnetic resonance imaging (MRI) is a surrogate method to measure calcium content in nervous system since manganese physiologically follows calcium. Manganese is detectable in MRI and therefore visualizes structures and cell populations that actively regulate calcium. Since calcium is actively recruited for the transmission of action potentials, our purpose is to validate manganese-enhanced MRI for detection of changes in lumbar nerves related to nociception. A neuropathic pain model was created by chronic constrictive injury of the left sciatic nerve of Sprague-Dawley rats. Behavioral measurements, using von Frey’s tests, confirmed the presence of significant allodynia in the left hind limb of animals in the injured group. T1-weighted fast spin echo images were obtained of the lumbar cord and plexus of animals with injured left sciatic nerve and uninjured animals (control) scanned in a 7 Tesla magnet after intraperitoneal manganese chloride administration four weeks after surgery. Lumbar nerve roots and sciatic nerves in the injured group show increased normalized manganese-enhanced MRI signal, representing manganese enhancement, compared to the control group. In conclusion, animals with neuropathic pain in the left hind limb show increased manganese uptake in not only the injured sciatic nerve but also in the contralateral uninjured sciatic nerve on manganese-enhanced MRI in vivo. Although poorly understood, this finding corroborates ex vivo finding of bilateral nociceptive-related molecular changes in the nervous system of unilateral pain models.

Behera, Deepak; Behera, Subrat; Jacobs, Kathleen E; Biswal, Sandip

2013-01-01

324

Polybenzoxazole via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

Polybenzoxazoles (PBO) are heterocyclic macromolecules which were first synthesized in a two-step process by the initial formation of aromatic diacid chlorides with bis(o-aminophenol)s through solution condensation of aromatic diacid chlorides with bis(o-aminophenol)s followed by thermal cyclodehydration. Since then several methods were utilized in their synthesis. The most common synthetic method for PBO involves a polycondensation of bis(o-aminophenol)s with aromatic diacid diphenyl esters. Another preparative route involves the solution polycondensation of the hydrochloride salts of bis(o-amino phenol)s with aromatic diacids in polyphosphoric acid. Another synthetic method involves the initial formation of poly(o-hydroxy amide)s from silylated bis(o-aminophenol)s with aromatic diacid chlorides followed by thermal cyclodehydration to PBO. A recent preparative route involves the reaction of aromatic bisphenols with bis(fluorophenyl) benzoxazoles by the displacement reaction to form PBO. The novelty of the present invention is that high molecular weight PBO of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

Hergenrother, Paul M. (inventor); Connell, John W. (inventor); Smith, Joseph G., Jr. (inventor)

1993-01-01

325

Ion Channels in Nerve Membranes  

ERIC Educational Resources Information Center

Discusses research that indicates that nerve membranes, which play a key role in the conduction of impulses, are traversed by protein channels with ion pathways opened and closed by the membrane electric field. (Author/MLH)

Ehrenstein, Gerald

1976-01-01

326

Oculomotor nerve palsies in children.  

PubMed

Fifty-four patients with oculomotor nerve palsy who presented over a 21-year period at our institution were reviewed retrospectively. There were 38 isolated third nerve lesions, and 16 with additional cranial nerve involvement. Eleven cases were congenital in origin, and 43 were acquired. Of the acquired group, 31 were traumatic, 7 infection-related, 3 attributed to migraine or other vascular causes, and 2 neoplastic. Average follow up was 36 months. The congenital lesions were predominantly right-sided; amblyopia, although common, responded well to treatment. Trauma and bacterial meningitis accounted for more cases of isolated oculomotor nerve palsy than seen in the previous literature. In distinct contrast to the adult population, no cases of diabetes, posterior communicating artery aneurysms, metastatic tumors, or pituitary lesions were found. PMID:1287170

Ing, E B; Sullivan, T J; Clarke, M P; Buncic, J R

1992-01-01

327

Large Extremity Peripheral Nerve Repair.  

National Technical Information Service (NTIS)

High velocity projectiles and fragments from improvised explosive devices (IED) cause traumatic tissue damage with approximately 20-30% of all extremity injuries and >80% of penetrating injuries being associated with peripheral nerve damage, typically inv...

J. M. Winograd M. E. Fleming R. W. Redmond

2013-01-01

328

Acute closed radial nerve injury  

PubMed Central

We present a 45-year-old patient who had acute radial nerve palsy following a blunt trauma without any fracture or dislocation. He was injured by strucking in a combat three months ago. The patient has been followed by application of a long-arm plaster cast before referred to our clinic. Preoperative electromyoneurography and magnetic resonance imaging (MRI) indicated that there was a radial nerve injury on humeral groove. The British Medical Research Council (MRC) grade was 2/5 on his wrist preoperatively. The patient underwent an operation under general anesthesia. It was seen to be a second-degree nerve injury. The patient has subsequently regained full movement on his wrist and finger extension in six months. We suggest that a detailed clinical and electrodiagnostical evaluation is necessary in patients who have radial nerve injury when deciding the treatment, conservative or surgical.

Tuncel, Umut; Turan, Aydin; Kostakoglu, Naci

2011-01-01

329

Tensile forces and failure characteristics of individual and bundles of roots embedded in soil - experiments and modeling  

NASA Astrophysics Data System (ADS)

The quantification of soil root reinforcement is relevant for many aspects of hillslope stability and forest management. The abundance and distribution of roots in upper soil layers determines slope stability and is considered a mitigating factor reducing shallow landslide hazard. Motivated by advances in modeling approaches that account for soil-root mechanical interactions at single root and bundle of roots of different geometries (the root bundle model - RBM), we set up a series of root pull out experiments in the laboratory and in the field to study the mechanical behavior of pulled roots. We focused on the role of displacement and root failure mechanisms in determining global tensile strength and failure dynamics in a root bundle. Strain controlled pull out tests of up to 13 roots in parallel each with its own force measurements provided insights into the detailed soil-root and bundle interactions . The results enabled systematic evaluation of factors such as root tortuosity and branching patterns for the prediction of single root pull out behavior, and demonstrated the importance of root diameter distribution for realistic prediction of global pullout behavior of a root bundle. Analyses of root-soil interface friction shows that force-displacement behavior varies for different combinations of soil types and water content. The maximal pull out interfacial friction ranges between 1 for wet sand (under 2 kPa confining pressure) and 17 kPa for dry sand (under 4.5 kPa confining pressure). These experiments were instrumental for calibration of the RBM which was later validated with six field experiments on natural root bundles of spruce (Picea abies L.). The tests demonstrated the progressive nature of failure of a bundle of roots under strain controlled conditions (such as formation of tension crack on a vegetated hillslope), and provide important insights regarding stress-strain behavior of natural root reinforcement.

Schwarz, Massimiliano; Cohen, Dedis; Or, Dani

2010-05-01

330

Retrograde tracing and toe spreading after experimental autologous nerve transplantation and crush injury of the sciatic nerve: a descriptive methodological study  

PubMed Central

Evaluation of functional and structural recovery after peripheral nerve injury is crucial to determine the therapeutic effect of a nerve repair strategy. In the present study, we examined the relationship between the structural evaluation of regeneration by means of retrograde tracing and the functional analysis of toe spreading. Two standardized rat sciatic nerve injury models were used to address this relationship. As such, animals received either a 2?cm sciatic nerve defect (neurotmesis) followed by autologous nerve transplantation (ANT animals) or a crush injury with spontaneous recovery (axonotmesis; CI animals). Functional recovery of toe spreading was observed over an observation period of 84?days. In contrast to CI animals, ANT animals did not reach pre-surgical levels of toe spreading. After the observation period, the lipophilic dye DiI was applied to label sensory and motor neurons in dorsal root ganglia (DRG; sensory neurons) and spinal cord (motor neurons), respectively. No statistical difference in motor or sensory neuron counts could be detected between ANT and CI animals. In the present study we could indicate that there was no direct relationship between functional recovery (toe spreading) measured by SSI and the number of labelled (motor and sensory) neurons evaluated by retrograde tracing. The present findings demonstrate that a multimodal approach with a variety of independent evaluation tools is essential to understand and estimate the therapeutic benefit of a nerve repair strategy.

2012-01-01

331

Retrograde tracing and toe spreading after experimental autologous nerve transplantation and crush injury of the sciatic nerve: a descriptive methodological study.  

PubMed

Evaluation of functional and structural recovery after peripheral nerve injury is crucial to determine the therapeutic effect of a nerve repair strategy. In the present study, we examined the relationship between the structural evaluation of regeneration by means of retrograde tracing and the functional analysis of toe spreading. Two standardized rat sciatic nerve injury models were used to address this relationship. As such, animals received either a 2?cm sciatic nerve defect (neurotmesis) followed by autologous nerve transplantation (ANT animals) or a crush injury with spontaneous recovery (axonotmesis; CI animals). Functional recovery of toe spreading was observed over an observation period of 84?days. In contrast to CI animals, ANT animals did not reach pre-surgical levels of toe spreading. After the observation period, the lipophilic dye DiI was applied to label sensory and motor neurons in dorsal root ganglia (DRG; sensory neurons) and spinal cord (motor neurons), respectively. No statistical difference in motor or sensory neuron counts could be detected between ANT and CI animals.In the present study we could indicate that there was no direct relationship between functional recovery (toe spreading) measured by SSI and the number of labelled (motor and sensory) neurons evaluated by retrograde tracing. The present findings demonstrate that a multimodal approach with a variety of independent evaluation tools is essential to understand and estimate the therapeutic benefit of a nerve repair strategy. PMID:22546145

van Neerven, Sabien Ga; Bozkurt, Ahmet; O'Dey, Dan Mon; Scheffel, Juliane; Boecker, Arne H; Stromps, Jan-Philipp; Dunda, Sebastian; Brook, Gary A; Pallua, Norbert

2012-01-01

332

Effects of Fault Displacement on Emplacement Drifts  

SciTech Connect

The purpose of this analysis is to evaluate potential effects of fault displacement on emplacement drifts, including drip shields and waste packages emplaced in emplacement drifts. The output from this analysis not only provides data for the evaluation of long-term drift stability but also supports the Engineered Barrier System (EBS) process model report (PMR) and Disruptive Events Report currently under development. The primary scope of this analysis includes (1) examining fault displacement effects in terms of induced stresses and displacements in the rock mass surrounding an emplacement drift and (2 ) predicting fault displacement effects on the drip shield and waste package. The magnitude of the fault displacement analyzed in this analysis bounds the mean fault displacement corresponding to an annual frequency of exceedance of 10{sup -5} adopted for the preclosure period of the repository and also supports the postclosure performance assessment. This analysis is performed following the development plan prepared for analyzing effects of fault displacement on emplacement drifts (CRWMS M&O 2000). The analysis will begin with the identification and preparation of requirements, criteria, and inputs. A literature survey on accommodating fault displacements encountered in underground structures such as buried oil and gas pipelines will be conducted. For a given fault displacement, the least favorable scenario in term of the spatial relation of a fault to an emplacement drift is chosen, and the analysis is then performed analytically. Based on the analysis results, conclusions are made regarding the effects and consequences of fault displacement on emplacement drifts. Specifically, the analysis will discuss loads which can be induced by fault displacement on emplacement drifts, drip shield and/or waste packages during the time period of postclosure.

F. Duan

2000-04-25

333

Optic Nerve Cysticercosis: Imaging Findings  

Microsoft Academic Search

Summary: We present the imaging findings of retrobulbar optic nerve cysticercosis in a 50-year-old woman with a 6- month history of vision loss. Contrast-enhanced CT re- vealed an approximately 7-mm ring-enhancing cyst with a mural nodule located in the anterior portion of the left op- tic nerve. A contrast-enhanced MR imaging study revealed a cystic lesion with peripheral enhancement of

Satish Chandra; Sushma Vashisht; Vimla Menon; Manorama Berry; Suresh K. Mukherji

334

Nerve Regeneration After Radiofrequency Application  

Microsoft Academic Search

Background: Many patients with chronic tendinosis have experienced early pain relief after application of bipolar radiofrequency treatment. It is hypothesized that the mechanism of action may be the acute degeneration and\\/or ablation of sensory nerve fibers.Hypothesis: After ablation or degeneration by bipolar radiofrequency, nerve fibers will have the ability to regenerate with time.Study Design: Controlled laboratory study.Methods: Eighteen Sprague-Dawley rats

Nobuyasu Ochiai; James P. Tasto; Seiji Ohtori; Norimasa Takahashi; Hideshige Moriya; David Amiel

2007-01-01

335

Assesing tree-root & soil interaction using pull-out test apparatus  

NASA Astrophysics Data System (ADS)

Knowing in situ root strength provides a better understanding of the responses of tree root systems against external loads. Root pullout devices are used to record these strengths and can be expressed in two ways: pullout force, which is a direct output from the load cell (measured in pounds) or pullout stress, which is the pullout force divided by root cross section area (measured in pounds per square in.). Pullout tests show not only the possible tensile strength of a tree root, but also the interaction between the tree root and the surrounding geological materials. After discussion with engineers from the University of Nottingham-Trent, the U.S. Army Engineer Research and Development Center (ERDC) constructed a root pullout apparatus with some modifications. These modifications included using a T-System configuration at the base of an aluminum frame instead of a diagonal rod and varying the size of the clamp placed around the tested root. The T-System is placed in front of the root perpendicular to the root path. In the ERDC pullout device, the root was pulled directly without a lever system. A string pot was used to measure displacement when the root was pulled. The device is capable of pulling tree roots with a diameter of up to 2.5 in. and a maximum load of 5000 lbs. Using this device, ERDC conducted field operations in Portland, Oregon; Burlington, Washington; and Albuquerque, New Mexico, on Oregon ash, alder, maple, and cedar trees. In general, pullout tests were conducted approximately 60 deg around the tree selected for the tests. The location of a test depended on the availability of a root near the ground surface. A backhoe was used to remove soil around the tree to locate roots. Before the root was secured in a clamp, root diameter was measured and recorded, and the root was photographed. The tree species, dip angle and dip direction of the root, root location with respect to the tree, tree location, dates, weather, and soil type were also recorded. When the test begins the load cell and displacement transducers immediately started recording the measurements, and the measurements are stored on a laptop computer. The hydraulic pump controls the rate of loading for a relatively slow pulling displacement rate of 0.08 in./sec. Failure occurred when the root breaks or was pulled out of the soil. Maximum forces and root failure location were noted, as well as any additional observations during and after the test. In the ERDC tests, root diameters (root with bark) ranged between 0.7 and 2.33 in., the pullout force was between 86 and 3513 lb, and the pullout stress was between 56 and 2645 psi. ERDC recorded three different types of tree-root failures: pure root tensile failure, bonding between root and soil failure, and a combination of the two. In tensile failure, a root breaks abruptly and the force versus displacement curve usually shows a steep slope, and there is no residual strength. In a bonding failure, the force versus displacement curve shows a gentler slope, and there is residual strength. A combined failure mode may also occur. For pullout tests conducted for the ERDC research, the combined mode failure was the most prevalent failure mechanism.

Wibowo, J.; Corcoran, M. K.; Kala, R.; Leavell, D.

2011-12-01

336

Hemangioma of the Facial Nerve  

PubMed Central

Hemangioma of the facial nerve may occur more frequently than previously recognized. This benign vascular tumor most often arises in the area of the geniculate ganglion, although the reason for this site of predilection is not known. Using silicon injection and cross-sectional vessel counts, we recently demonstrated the presence of a geniculate capillary plexus (GCP) in the cat. The present study was designed to identify a similar GCP in man, if present, and to relate if to the site of predilection of hemangioma of the facial nerve. Twenty-five human facial nerves were studied in horizontally sectioned temporal bones. A clinical case of hemangioma arising at the geniculate ganglion is presented. The human geniculate ganglion has a very rich capillary plexus in contrast to the poor intrinsic vasculature of the adjacent labyrinthine segment and nioderate vasculature of the tympanic segment of the facial nerve. We hypothesize that the GCP is the origin of most hemangiomas of facial nerve. The anatomic distinctness of the geniculate gangion and GCP from the facial nerve may allow removal of these tumors with preservation of motor function in certain cases. ImagesFigure 1Figure 2Figure 3

Balkany, Thomas; Fradis, Milo; Jafek, Bruce W.; Rucker, Nolan C.

1991-01-01

337

Posterior femoral cutaneous nerve conduction.  

PubMed

The posterior femoral cutaneous nerve is a sensory nerve comprised of fibers originating from the anterior and posterior divisions of the first three sacral segments. It exists the pelvis distal to the piriformis muscle and proceeds distally, superficial to and between the medial and lateral hamstring musculature. The nerve's major cutaneous distribution is the posterior aspect of the thigh and a variable area of the posterior calf. An electrophysiologic technique to assess the peripheral axons of the posterior femoral cutaneous nerve is described. A recording electrode is placed 6cm proximal to the midpopliteal fossa and the nerve is stimulated supramaximally 12cm proximally on a line between the active electrode and the ischial tuberosity. A ground electrode is placed just proximal to the active recording electrode. The lower extremities of 40 individuals with a mean age of 34 years (20 to 78 years) were examined. The mean peak latency of the response is 2.8 (2.3 to 3.4) msec +/- 0.2msec with a mean amplitude of 6.5 (4.1 to 12.0) microV +/- 1.5 microV. This technique may facilitate the proximal evaluation of lower extremity peripheral neuropathies, lesions of the posterior femoral cutaneous nerve, or the assessment of the peripheral nervous system in persons with lower extremity amputations. PMID:2241545

Dumitru, D; Nelson, M R

1990-11-01

338

Optic nerve head segmentation.  

PubMed

Reliable and efficient optic disk localization and segmentation are important tasks in automated retinal screening. General-purpose edge detection algorithms often fail to segment the optic disk due to fuzzy boundaries, inconsistent image contrast or missing edge features. This paper presents an algorithm for the localization and segmentation of the optic nerve head boundary in low-resolution images (about 20 microns/pixel). Optic disk localization is achieved using specialized template matching, and segmentation by a deformable contour model. The latter uses a global elliptical model and a local deformable model with variable edge-strength dependent stiffness. The algorithm is evaluated against a randomly selected database of 100 images from a diabetic screening programme. Ten images were classified as unusable; the others were of variable quality. The localization algorithm succeeded on all bar one usable image; the contour estimation algorithm was qualitatively assessed by an ophthalmologist as having Excellent-Fair performance in 83% of cases, and performs well even on blurred images. PMID:14964569

Lowell, James; Hunter, Andrew; Steel, David; Basu, Ansu; Ryder, Robert; Fletcher, Eric; Kennedy, Lee

2004-02-01

339

Optic Nerve Monitoring  

PubMed Central

Orbital and anterior skull base surgery is generally performed close to the prechiasmatic visual pathway, and clear strategies for detecting and handling visual pathway damage are essential. To overcome the common problem of a missed clinical examination because of an uncooperative or unresponsive patient, flash visual evoked potentials and electroretinograms should be used. These electrophysiologic examination techniques can provide evidence of intact, pathologic, or absent conductivity of the visual pathway when clinical assessment is not feasible. Visual evoked potentials and electroretinograms are thus essential diagnostic procedures not only for primary diagnosis but also for intraoperative evaluation. A decision for or against treatment of a visual pathway injury has to be made as fast as possible due to the enormous importance of the time elapsed with such injuries; this can be achieved additionally using multislice spiral computed tomography. The first-line conservative treatment of choice for such injuries is megadose methylprednisolone therapy. Surgery is used to decompress the orbital compartment by exposure of the intracanalicular part of the optic nerve in the case of optic canal compression. Modern craniomaxillofacial surgery requires detailed consideration of the diagnosis and treatment of traumatic visual pathway damage with the ultimate goal of preserving visual acuity.

Schumann, Paul; Kokemuller, Horst; Tavassol, Frank; Lindhorst, Daniel; Lemound, Juliana; Essig, Harald; Rucker, Martin; Gellrich, Nils-Claudius

2013-01-01

340

Optic nerve monitoring.  

PubMed

Orbital and anterior skull base surgery is generally performed close to the prechiasmatic visual pathway, and clear strategies for detecting and handling visual pathway damage are essential. To overcome the common problem of a missed clinical examination because of an uncooperative or unresponsive patient, flash visual evoked potentials and electroretinograms should be used. These electrophysiologic examination techniques can provide evidence of intact, pathologic, or absent conductivity of the visual pathway when clinical assessment is not feasible. Visual evoked potentials and electroretinograms are thus essential diagnostic procedures not only for primary diagnosis but also for intraoperative evaluation. A decision for or against treatment of a visual pathway injury has to be made as fast as possible due to the enormous importance of the time elapsed with such injuries; this can be achieved additionally using multislice spiral computed tomography. The first-line conservative treatment of choice for such injuries is megadose methylprednisolone therapy. Surgery is used to decompress the orbital compartment by exposure of the intracanalicular part of the optic nerve in the case of optic canal compression. Modern craniomaxillofacial surgery requires detailed consideration of the diagnosis and treatment of traumatic visual pathway damage with the ultimate goal of preserving visual acuity. PMID:24436741

Schumann, Paul; Kokemüller, Horst; Tavassol, Frank; Lindhorst, Daniel; Lemound, Juliana; Essig, Harald; Rücker, Martin; Gellrich, Nils-Claudius

2013-06-01

341

BLOCK DISPLACEMENT METHOD FIELD DEMONSTRATION AND SPECIFICATIONS  

EPA Science Inventory

The Block Displacement technique has been developed as a remedial action method for isolating large tracks of ground contaminated by hazardous waste. The technique places a low permeability barrier around and under a large block of contaminated earth. The Block Displacement proce...

342

A microfabricated electrochemical actuator for large displacements  

Microsoft Academic Search

A large-displacement electrochemical actuator was designed, fabricated, and tested. The large displacement is obtained by using a corrugated membrane made by physical vapor deposition of Parylene sandwiched with an intermediate layer of sputtered platinum. The layered structure is approximately 8-?m thick, with 26 grooves approximately 120-?m deep, and with a radial period of 350 ?m. The electrochemical cell consists of

Tom Stanczyk; B. Ilic; Peter J. Hesketh; James G. Boyd

2000-01-01

343

Displaced femoral neck fractures in the elderly  

Microsoft Academic Search

This study evaluated the relationship of the disposition and outcome of patients with displaced femoral neck fractures with the type of surgical treatment. From 1993 to 1996, 186 patients with displaced femoral neck fractures who were 65 years of age or older were treated at one hospital. One hundred and twenty fractures were treated with reduction and internal fixation; 66

Richard Iorio; William L Healy; David Appleby; John Milligan; Michael Dube

2004-01-01

344

Gas Miscible Displacement Enhanced Oil Recovery.  

National Technical Information Service (NTIS)

The general goal of the Gas Miscible Displacement Project is to support high-risk, long-term CO sub 2 /EOR research that does not duplicate or displace private and other public R and D efforts. More specifically, the project goals are: (1) to understand t...

1984-01-01

345

Horizontal displacements of rock foundations of dams  

SciTech Connect

This paper uses geodetic survey methods to assess the horizontal displacements of dam foundations for several hydroelectric power plants in the Soviet Union. The effects of filling the reservoirs are outlined and the dependence of the degree of displacement on dam height is analyzed. The results are tabulated.

Karlson, A.A.

1987-08-01

346

The effects of delayed nerve repair on neuronal survival and axonal regeneration after seventh cervical spinal nerve axotomy in adult rats.  

PubMed

It has been proposed clinically that delayed surgery after traumatic brachial plexus injury may adversely affect functional outcome. In the present experimental study the neuroprotective and growth-promoting effects of early and delayed nerve grafting following proximal seventh cervical spinal nerve (C7) axotomy were examined. The ventral branch of C7 spinal nerve was transected and axons projecting out of the proximal nerve stump were labelled with Fast Blue (FB). At the same time, the biceps brachii muscle was denervated by transecting the musculocutaneous nerve at its origin. Neuronal survival and muscle atrophy were then assessed at 1, 4, 8 and 16 weeks after permanent axotomy. In the experimental groups, a peripheral nerve graft was interposed between the transected C7 spinal nerve and the distal stump of the musculocutaneous nerve at 1 week [early nerve repair (ENR)] or 8 weeks [delayed nerve repair (DNR)] after axotomy. Sixteen weeks after nerve repair had been performed, a second tracer Fluoro-Ruby (FR) was applied distal to the graft to assess the efficacy of axonal regeneration. Counts of FB-labelled neurons revealed that axotomy did not induce any significant cell loss at 4 weeks, but 15% of motoneurons and 32% of sensory neurons died at 8 weeks after injury. At 16 weeks, the amount of cell loss in spinal cord and dorsal root ganglion (DRG) reached 29 and 50%, respectively. Both ENR and DNR prevented retrograde degeneration of spinal motoneurons and counteracted muscle atrophy, but failed to rescue sensory neurons. Due to substantial cell loss at 8 weeks, the number of FR-labelled neurons after DNR was significantly lower when compared to ENR. However, the proportion of regenerating neurons among surviving motoneurons and DRG neurons remained relatively constant indicating that neurons retained their regenerative capacity after prolonged axotomy. The results demonstrate that DNR could protect spinal motoneurons and reduce muscle atrophy, but had little effect on sensory DRG neurons. However, the efficacy of neuroprotection and axonal regeneration will be significantly affected by the amount of cell loss already presented at the time of nerve repair. PMID:16328277

Jivan, Sharmila; Novikova, Liudmila N; Wiberg, Mikael; Novikov, Lev N

2006-04-01

347

Using a 2D displacement sensor to derive 3D displacement information  

NASA Technical Reports Server (NTRS)

A 2D displacement sensor is used to measure displacement in three dimensions. For example, the sensor can be used in conjunction with a pulse-modulated or frequency-modulated laser beam to measure displacement caused by deformation of an antenna on which the sensor is mounted.

Soares, Schubert F. (Inventor)

2002-01-01

348

The deformation field around a point displacement in a gel  

NASA Astrophysics Data System (ADS)

We study the deformation field around a point displacement in a fractal colloidal gel. The samples are formed by diffusion-limited cluster aggregation (DLCA) of latex spheres with a small number of paramagnetic latex spheres. An external magnetic field is applied and the motions of the latex spheres are probed with an optical microscope. Using IDL particle tracking software, we obtain the particle positions. The deformation field is compared to the local structure in order to investigate the local elasticity. We also measure each particle's localization length, which is the root mean square deviation from the particle's time-averaged position. It has been found that disordered solids share a common distribution of normalized localization lengths; we investigate whether this distribution is the same under conditions of applied stress. The results of our measurements will be helpful to test statistical mechanical predictions of universal properties of disordered solids. We acknowledge support from the donors of the American Chemical Society Petroleum Research Fund.

Kang, Wenfeng; Dinsmore, A. D.

2004-03-01

349

The root endodermis  

PubMed Central

The root endodermis is the cylindrical boundary that separates the inner vascular tissue from the outer cortex and functions as an apoplasmic barrier for selective nutrient uptake. Recent developmental and cell biological studies have started to reveal the mechanisms by which this single cell layer serves as a key regulatory module of root growth, tissue patterning and nutrient flow, which in concert support the plant’s ability to survive in a terrestrial habitat. This review provides an overview of the key factors that contribute to the functioning of the root endodermis and discusses how this single cell layer dictates root growth and tissue patterning.

Miyashima, Shunsuke

2011-01-01

350

The effects of gradients of nerve growth factor immobilized PCLA scaffolds on neurite outgrowth in vitro and peripheral nerve regeneration in rats.  

PubMed

Introducing concentration gradients of nerve growth factor (NGF) into conduits for repairing of peripheral nerve injury is crucial for nerve regeneration and guidance. Herein, combining differential adsorption of NGF/silk fibroin (SF) coating, the gradient of NGF-immobilized membranes (G-Ms) and nanofibrous nerve conduits (G-nNCs) were successfully fabricated. The efficacy of NGF gradients was confirmed by a quantitative comparison of dorsal root ganglia (DRG) neurite outgrowth on the G-Ms or uniform NGF-immobilized membranes (U-Ms). Significantly, the neurite turning ratio was 0.48 ± 0.11 for G-M group, but it was close to zero for U-M group. The neurite length of DRGs in the middle of the G-Ms was significantly longer than that of U-M group, even though the average NGF concentration was approximated. Furthermore, 12 weeks after implantation in rats with a 14 mm gap of sciatic nerve injury, G-nNCs achieved satisfying outcomes of nerve regeneration associated with morphological and functional improvements, which was superior to that of the uniform NGF-immobilized nNCs (U-nNCs). Sciatic function index (SFI), compound muscle action potentials (CMAPs), total number of myelinated nerve fibers, thickness of myelin sheath were similar for the G-nNCs and autografts, with the G-nNCs having a higher density of axons than the autografts. Our results demonstrated the significant role of introducing NGF gradients into scaffolds in promoting nerve regeneration. PMID:23791502

Tang, Shuo; Zhu, Jixiang; Xu, Yangbin; Xiang, Andy Peng; Jiang, Mei Hua; Quan, Daping

2013-09-01

351

Effect of crush lesion on radiolabelling of ganglioside in rat peripheral nerve.  

PubMed

Left sciatic nerves of adult male Sprague-Dawley rats were crushed and allowed to recover for 0, 1, 2, 4, 7, or 14 days. At each of these times both L-5 dorsal root ganglia were injected with 100 microCi of [3H]glucosamine. Two days later, dorsal root ganglia, lumbosacral trunks, and sciatic nerves were removed bilaterally. The amounts of radiolabelled ganglioside in crushed lumbosacral trunks were consistently higher than in the controls, with the largest difference occurring within 2 days from simultaneous crush and injection to killing (specimens labelled day 0). The largest difference in the amount of radiolabelled ganglioside between crushed and control sciatic nerve (4-9 days from crush to killing) occurred later than that of lumbosacral trunk, but no significant difference occurred within the first 3 days following crush. There was only a slightly higher radioactivity in gangliosides totalled from all three anatomical specimens of crushed than in control nerves. The neutral nonganglioside lipid and acid-precipitable fraction followed patterns of synthesis and accumulation similar to those of the gangliosides. These findings indicate that after nerve crush gangliosides, glucosamine-labelled neutral nonganglioside lipids, and glycoproteins accumulate close to the proximal end of the regenerating axon. This accumulation could serve as a reservoir to increase the ganglioside concentration in the growth cone membrane. PMID:3335841

Guzman-Harty, M; Warner, J K; Mancini, M E; Pearl, D K; Yates, A J

1988-01-01

352

Ulnar nerve at the elbow - normative nerve conduction study  

PubMed Central

Introduction A goal of our work was to perform nerve conduction studies (NCSs) of the ulnar nerve focused on the nerve conduction across the elbow on a sufficiently large cohort of healthy subjects in order to generate reliable reference data. Methods We examined the ulnar nerve in a position with the elbow flexion of 90o from horizontal. Motor response was recorded from the abductor digiti minimi muscle (ADM) and the first dorsal interosseous muscle (FDI). Results In our sample of 227 healthy volunteers we have examined 380 upper arms with the following results: amplitude (Amp)-CMAP(wrist) for ADM 9.6 ± 2.3 mV, MNCV at the forearm 60.4 ± 5.2 m/s, MNCV across the elbow 57.1 ± 5.9 m/s. Discussion Our study showed that motor NCSs of the ulnar nerve above elbow (AE) and below elbow (BE) in a sufficiently large cohort using methodology recommended by AANEM gave results well comparable for registration from FDI and ADM.

2013-01-01

353

Assessment of nerve involvement in the lumbar spine: agreement between magnetic resonance imaging, physical examination and pain drawing findings  

PubMed Central

Background Detection of nerve involvement originating in the spine is a primary concern in the assessment of spine symptoms. Magnetic resonance imaging (MRI) has become the diagnostic method of choice for this detection. However, the agreement between MRI and other diagnostic methods for detecting nerve involvement has not been fully evaluated. The aim of this diagnostic study was to evaluate the agreement between nerve involvement visible in MRI and findings of nerve involvement detected in a structured physical examination and a simplified pain drawing. Methods Sixty-one consecutive patients referred for MRI of the lumbar spine were - without knowledge of MRI findings - assessed for nerve involvement with a simplified pain drawing and a structured physical examination. Agreement between findings was calculated as overall agreement, the p value for McNemar's exact test, specificity, sensitivity, and positive and negative predictive values. Results MRI-visible nerve involvement was significantly less common than, and showed weak agreement with, physical examination and pain drawing findings of nerve involvement in corresponding body segments. In spine segment L4-5, where most findings of nerve involvement were detected, the mean sensitivity of MRI-visible nerve involvement to a positive neurological test in the physical examination ranged from 16-37%. The mean specificity of MRI-visible nerve involvement in the same segment ranged from 61-77%. Positive and negative predictive values of MRI-visible nerve involvement in segment L4-5 ranged from 22-78% and 28-56% respectively. Conclusion In patients with long-standing nerve root symptoms referred for lumbar MRI, MRI-visible nerve involvement significantly underestimates the presence of nerve involvement detected by a physical examination and a pain drawing. A structured physical examination and a simplified pain drawing may reveal that many patients with "MRI-invisible" lumbar symptoms need treatment aimed at nerve involvement. Factors other than present MRI-visible nerve involvement may be responsible for findings of nerve involvement in the physical examination and the pain drawing.

2010-01-01

354

Cranial nerve injury during carotid arterial reconstruction.  

PubMed

In a series of 109 carotid arterial reconstructions cranial nerve injury was observed in 14 of 102 patients. Ipsilateral peripheral hypoglossal nerve injury occurred in nine patients with carotid occlusive disease. The marginal mandibular nerve was injured in three patients and recurrent laryngeal nerve dysfunction was noted in four patients. Two cranial nerves were injured in two patients. Full recovery of hypoglossal dysfunction was seen within 2-52 weeks (average 20 weeks). The nerves are injured by retraction to clear the operative field or by postoperative haematoma. Risk factors include crossing of the hypoglossal nerve close to the carotid bifurcation or procedures requiring long arteriotomy or skeletonization of the internal carotid artery. Unilateral cranial nerve injury is usually mild but will require delay of controlateral carotid reconstruction to avoid severe bilateral cranial nerve palsy. PMID:6196459

Schmidt, D; Zuschneid, W; Kaiser, M

1983-01-01

355

Myelinated afferents signal the hyperalgesia associated with nerve injury.  

PubMed

Pain to light touching of the skin is a hallmark sign of causalgia. The purpose of this study was to determine whether myelinated or unmyelinated afferent fibers signal this hyperalgesia. Sensory testing was performed in 17 patients with long-standing hyperalgesia after nerve injury. The patients underwent a differential ischemic block of nerve function of the involved area. At a time when touch sensation in adjacent normal skin was eliminated, but when sensibility to warming and cooling stimuli was unaffected, the hyperalgesia to mechanical stimuli was abolished in 15 of the subjects. In 2 of these 15 patients, a differential local anesthetic block of the injured nerve was performed proximal to the site of injury. When temperature sensibility was absent, but when touch sensation was intact, hyperalgesia was present. In a third study, latency measurements in response to 400 micron stepped displacement stimuli were made in two patients who had hyperalgesia on the foot. The mean latency for detection of pain in the hyperalgesic region was 414 +/- 18 msec, compared to 458 +/- 16 msec for the detection of touch to the same stimuli applied to the opposite normal foot. These 3 lines of evidence indicate that myelinated primary afferents, perhaps A beta fibers, signal the hyperalgesic pain in causalgia. These fibers may be sensitized A beta nociceptors or low-threshold mechanoreceptors. PMID:3340426

Campbell, J N; Raja, S N; Meyer, R A; Mackinnon, S E

1988-01-01

356

Topography and time course of changes in spinal neuropeptide Y immunoreactivity after spared nerve injury  

PubMed Central

We used a new computer-assisted method to precisely localize and efficiently quantify increases in NPY immunoreactivity (NPY-ir) along the mediolateral axis of the L4 dorsal horn following transection of either the tibial and common peroneal nerves (thus sparing the sural branch, spared nerve injury, SNI), the tibial nerve, or the common peroneal and sural nerves. Two weeks after SNI, NPY-ir increased within the tibial and peroneal innervation territories; however, NPY-ir in the central-lateral region (innervated by the spared sural nerve) was indistinguishable from that of SHAM. Conversely, transection of the sural and common peroneal nerved induced an increase in NPY-ir in the central-lateral region, while leaving the medial region (innervated by the tibial nerve) unaffected. All nerve injuries increased NPY-ir in dorsal root ganglia (DRG) and nucleus gracilis (NG). By 24 wk, both NPY-ir up-regulation in the dorsal horn and hyper-responsivity to cold and noxious mechanical stimuli had resolved. Conversely, NPY-ir in DRG and NG, and hypersensitivity to non-noxious static mechanical stimuli, did not resolve within 24 wk. Over this time course, the average cross-sectional area of NPY-immunoreactive DRG neurons increased by 150 ?m2. We conclude that the up-regulation of NPY after SNI is restricted to medial zones of the dorsal horn, and therefore cannot act directly upon synapses within the more lateral (sural) zones to control sural nerve hypersensitivity. Instead, we suggest that NPY in the medial dorsal horn tonically inhibits hypersensitivity by interrupting mechanisms of central sensitization and integration of sensory signals at the spinal and supraspinal levels.

Intondi, A.B.; Zadina, J.E.; Zhang, X.; Taylor, B.K.

2009-01-01

357

Controlled Field and Laboratory Experiments to Investigate soil-root Interactions and Streambank Stability.  

NASA Astrophysics Data System (ADS)

Riparian vegetation has a number of mechanical and hydrologic effects on streambank stability, some of which are positive and some of which are negative. The mechanical reinforcement provided by root networks is one of the most important stabilizing factors, as roots are strong in tension but weak in compression and conversely soil is strong in compression but weak in tension. A soil that contains roots therefore has increased shear strength due to the production of a reinforced matrix, which is stronger than the soil or roots separately (Thorne, 1990). Quantification and understanding of the way the soil and roots interact individually and as a complete matrix is important if we are to predict the reinforcing effects of different types of riparian vegetation in streambank stabilizing schemes. Previous estimates of the contribution of root networks to soil strength have been attained either by using equations that sum root tensile and the soil shear strengths (eg. Wu et al., 1979), or by carrying out shear tests of root-permeated soils. However, neither of these methods alone allows a full investigation and understanding of the interactions that take place between the soil and the roots as a soil is sheared. These interactions are complex, and the simple addition of root tensile and soil shear strengths may therefore lead to overestimation of the increased strength provided to the soil by the roots, as the rate of mobilization of stress in the roots may not be the same as that of the soil (Waldron and Dakessian, 1981; Pollen et al., 2002). This paper describes a series of experiments that were carried out to test the material properties of roots, and soil samples from a streambank along Goodwin Creek, N. Mississippi. Results from field experiments carried out to measure root-tensile strengths, and stress-displacement characteristics of roots, were compared with laboratory shear tests of soil samples from Goodwin Creek. It was shown that the roots of different species took up strain at different rates, and that these rates differed considerably from that of the Goodwin Creek soil sample. For example, the mean displacement of Eastern Sycamore roots before breaking was 3.57cm, whereas the displacement of the soil sample at peak strength was just 0.68cm, suggesting that the critical factor in root reinforcement of soil matrices may in fact be the rate of mobilization of tension in the roots, rather than their ultimate tensile strength. Isolation and testing of the roots and soil separately, in the field and the laboratory, allowed the formulation of two hypotheses to explain the way in which roots and soil interact during shearing: As the soil shears, either the roots reinforce the soil after the peak soil strength has been overcome, until the ultimate tensile strength of the roots is reached, or the roots only reinforce the soil until the peak soil strength has been reached, beyond which point the entire root-soil matrix fails. These hypotheses were then tested by running a series of laboratory-shear tests of root-permeated and non-root-permeated soils. The results of these studies were used in the ARS-Bank Stability Model (ver. 2.0) to simulate the increase in factor of safety of streambanks due to root reinforcement. The calculations suggest that overestimation of increased soil shear strength from the root network using the sum of root tensile and soil shear strengths, may be as high as 78% for Eastern Sycamore roots which uptake strain slowly, but only 10% for Sandbar Willow roots, which take up tension more quickly.

Pollen, N. L.; Simon, A.

2002-12-01

358

An ecohydrological framework for grass displacement by woody plants in savannas  

NASA Astrophysics Data System (ADS)

the past several decades, woody plants have been encroaching into grasslands around the world. This transition in plant dominance is often explained as a state shift in bistable ecosystem dynamics induced by fire-vegetation feedbacks. These feedbacks occur when woody plants are able to displace grasses because of their better access to soil water and light. On the other hand, grasses can displace woody plants because of their ability to increase fire frequency and of the higher susceptibility of woody plants to fire-induced mortality. In this study, we present an ecohydrological framework to investigate the displacement of grasses by woody plants. Considering the effect of lateral root spread and of soil water and light limitations, we found that woody plant encroachment can substantially suppress grass production even without the presence of grazers. Bistable dynamics emerge as a result of the grass-fire feedback for a wide range of rainfall conditions, fire susceptibility, and woody plant growth rates.

Yu, Kailiang; D'Odorico, Paolo

2014-03-01

359

Development and Evolution of Character Displacement  

PubMed Central

Character displacement occurs when competition for either resources or successful reproduction imposes divergent selection on interacting species, causing divergence in traits associated with resource use or reproduction. Here, we describe how character displacement can be mediated either by genetically canalized changes (i.e., changes that reflect allelic or genotype frequency changes) or by phenotypic plasticity. We also discuss how these two mechanisms influence the tempo of character displacement. Specifically, we suggest that, under some conditions, character displacement mediated by phenotypic plasticity might occur more rapidly than that mediated by genetically canalized changes. Finally, we describe how these two mechanisms may act together and determine character displacement’s mode, such that it proceeds through an initial phase in which trait divergence is environmentally induced to a later phase in which divergence becomes genetically canalized. This plasticity-first hypothesis predicts that character displacement should be generally mediated by ancestral plasticity and that it will arise similarly in multiple, independently evolving populations. We conclude by highlighting future directions for research that would test these predictions.

Pfennig, David W.; Pfennig, Karin S.

2012-01-01

360

Ophthalmoplegic migraine with trigeminal nerve involvement.  

PubMed

We report a 25-year-old man with a history of uncontrolled migrainous headaches who developed third nerve palsy and sensory loss over V1 distribution of trigeminal nerve, during an attack of severe migraine. Gadolinium-enhanced MRI of the brain and cavernous sinus was normal and did not disclose nerve enhancement. CT angiogram was also normal. The patient recovered uneventfully in 2 weeks on oral steroids. The commonest cranial nerve implicated in ophthalmoplegic migraine is the occulomotor nerve. Involvement of the fifth nerve has never been reported. PMID:23715838

Sharma, Bhawna; Sannegowda, Raghavendra Bakki; Kumar, Sunil; Dubey, Parul

2013-01-01

361

Displacement fields from point cloud data: Application of particle imaging velocimetry to landslide geodesy  

NASA Astrophysics Data System (ADS)

Acquiring spatially continuous ground-surface displacement fields from Terrestrial Laser Scanners (TLS) will allow better understanding of the physical processes governing landslide motion at detailed spatial and temporal scales. Problems arise, however, when estimating continuous displacement fields from TLS point-clouds because reflecting points from sequential scans of moving ground are not defined uniquely, thus repeat TLS surveys typically do not track individual reflectors. Here, we implemented the cross-correlation-based Particle Image Velocimetry (PIV) method to derive a surface deformation field using TLS point-cloud data. We estimated associated errors using the shape of the cross-correlation function and tested the method's performance with synthetic displacements applied to a TLS point cloud. We applied the method to the toe of the episodically active Cleveland Corral Landslide in northern California using TLS data acquired in June 2005-January 2007 and January-May 2010. Estimated displacements ranged from decimeters to several meters and they agreed well with independent measurements at better than 9% root mean squared (RMS) error. For each of the time periods, the method provided a smooth, nearly continuous displacement field that coincides with independently mapped boundaries of the slide and permits further kinematic and mechanical inference. For the 2010 data set, for instance, the PIV-derived displacement field identified a diffuse zone of displacement that preceded by over a month the development of a new lateral shear zone. Additionally, the upslope and downslope displacement gradients delineated by the dense PIV field elucidated the non-rigid behavior of the slide.

Aryal, Arjun; Brooks, Benjamin A.; Reid, Mark E.; Bawden, Gerald W.; Pawlak, Geno R.

2012-03-01

362

Results of ulnar nerve neurotization to biceps brachii muscle in brachial plexus injury  

PubMed Central

OBJECTIVE: To evaluate the factors influencing the results of ulnar nerve neurotization at the motor branch of the brachii biceps muscle, aiming at the restoration of elbow flexion in patients with brachial plexus injury. METHODS: 19 patients, with 18 men and 1 woman, mean age 28.7 years. Eight patients had injury to roots C5-C6 and 11, to roots C5-C6-C7. The average time interval between injury and surgery was 7.5 months. Four patients had cervical fractures associated with brachial plexus injury. The postoperative follow-up was 15.7 months. RESULTS: Eight patients recovered elbow flexion strength MRC grade 4; two, MRC grade 3 and nine, MRC <3. There was no impairment of the previous ulnar nerve function. CONCLUSION: The surgical results of ulnar nerve neurotization at the motor branch of brachii biceps muscle are dependent on the interval between brachial plexus injury and surgical treatment, the presence of associated fractures of the cervical spine and occipital condyle, residual function of the C8-T1 roots after the injury and the involvement of the C7 root. Signs of reinnervation manifested up to 3 months after surgery showed better results in the long term. Level of Evidence: IV, Case Series.

Rezende, Marcelo Rosa De; Rabelo, Neylor Teofilo Araujo; Silveira, Clovis Castanho; Petersen, Pedro Araujo; Paula, Emygdio Jose Leomil De; Mattar, Rames

2012-01-01

363

ROOTING GUATEMALAN AVOCADO CUTTINGS  

Microsoft Academic Search

SUMMARY A method is described which, although not considered commercially practical, proved to be very successful in rooting cuttings of Guatemalan avocado varieties. Essentially it consists of obtaining cuttings from stems, the bases of which have at no time been exposed to light or low humidity. In certain experimental work with the avocado, own rooted trees, that is trees propagated

E. F. Frolich

364

Irrational Square Roots  

ERIC Educational Resources Information Center

If students are presented the standard proof of irrationality of [square root]2, can they generalize it to a proof of the irrationality of "[square root]p", "p" a prime if, instead of considering divisibility by "p", they cling to the notions of even and odd used in the standard proof?

Misiurewicz, Michal

2013-01-01

365

Seeds: Roots and Shoots  

NSDL National Science Digital Library

In this indepth hands-on activity, learners build a structure that allows them to observe the growth of roots and the correlation between root growth and stem extension. Because no dirt is used in this arrangement, a guiding question can be posed: What does the plant need to grow? The PDF includes activity rationale, procedure, background and follow-up discussion suggestions.

Education Development Center, Inc.

2010-01-01

366

Anion-exchange displacement centrifugal partition chromatography.  

PubMed

Ion-exchange displacement chromatography has been adapted to centrifugal partition chromatography. The use of an ionic liquid, benzalkonium chloride, as a strong anion-exchanger has proven to be efficient for the preparative separation of phenolic acid regioisomers. Multigram quantities of a mixture of three hydroxycinnamic acid isomers were separated using iodide as a displacer. The displacement process was characterized by a trapezoidal profile of analyte concentration in the eluate with narrow transition zones. By taking advantage of the partition rules involved in support-free liquid-liquid chromatography, a numerical separation model is proposed as a tool for preliminary process validation and further optimization. PMID:15516108

Maciuk, Alexandre; Renault, Jean-Hugues; Margraff, Rodolphe; Trébuchet, Philippe; Zèches-Hanrot, Monique; Nuzillard, Jean-Marc

2004-11-01

367

[Connection of trigeminal nerve and facial nerve branches and its clinical significance].  

PubMed

In recent years, many anatomical researches have showed that there are common and extensive connections between the trigeminal nerve and the facial nerve.They are briefly outlined as follows: (1) The infraorbital nerve communicates with buccal branch of the facial nerve. (2) The auriculotemporal nerve of the trigeminal nerve communicates with the buccal, zygomatic,temporal branches and the upper divisions of the facial nerve. (3) The supraorbital nerve communicates with the zygomatic and temporal branches of the facial nerve. (4) The mental nerve communicates with the marginal mandibular branch of the facial nerve. (5) The buccinator nerve communicates with the zygomatic, buccal and marginal mandibular branches. These communications between the trigeminal nerve and facial nerve are probably related to several clinical signs, for example,some trigeminal neuralgia patients are complicated by facial spasm, some patients appeared spontaneous partial functional recovery of mimetic muscles following surgical resection of a considerable segment of the facial nerve (including a portion of its main trunk and the peripheral plexus), etc. The purpose of this article was to review the anatomical features and clinical significance of the communications between the trigeminal nerve and the facial nerve. PMID:19907866

Li, Chao; Jiang, Xiao-zhong; Zhao, Yun-fu

2009-10-01

368

PDT - PARTICLE DISPLACEMENT TRACKING SOFTWARE  

NASA Technical Reports Server (NTRS)

Particle Imaging Velocimetry (PIV) is a quantitative velocity measurement technique for measuring instantaneous planar cross sections of a flow field. The technique offers very high precision (1%) directionally resolved velocity vector estimates, but its use has been limited by high equipment costs and complexity of operation. Particle Displacement Tracking (PDT) is an all-electronic PIV data acquisition and reduction procedure which is simple, fast, and easily implemented. The procedure uses a low power, continuous wave laser and a Charged Coupled Device (CCD) camera to electronically record the particle images. A frame grabber board in a PC is used for data acquisition and reduction processing. PDT eliminates the need for photographic processing, system costs are moderately low, and reduced data are available within seconds of acquisition. The technique results in velocity estimate accuracies on the order of 5%. The software is fully menu-driven from the acquisition to the reduction and analysis of the data. Options are available to acquire a single image or 5- or 25-field series of images separated in time by multiples of 1/60 second. The user may process each image, specifying its boundaries to remove unwanted glare from the periphery and adjusting its background level to clearly resolve the particle images. Data reduction routines determine the particle image centroids and create time history files. PDT then identifies the velocity vectors which describe the particle movement in the flow field. Graphical data analysis routines are included which allow the user to graph the time history files and display the velocity vector maps, interpolated velocity vector grids, iso-velocity vector contours, and flow streamlines. The PDT data processing software is written in FORTRAN 77 and the data acquisition routine is written in C-Language for 80386-based IBM PC compatibles running MS-DOS v3.0 or higher. Machine requirements include 4 MB RAM (3 MB Extended), a single or multiple frequency RGB monitor (EGA or better), a math co-processor, and a pointing device. The printers supported by the graphical analysis routines are the HP Laserjet+, Series II, and Series III with at least 1.5 MB memory. The data acquisition routines require the EPIX 4-MEG video board and optional 12.5MHz oscillator, and associated EPIX software. Data can be acquired from any CCD or RS-170 compatible video camera with pixel resolution of 600hX400v or better. PDT is distributed on one 5.25 inch 360K MS-DOS format diskette. Due to the use of required proprietary software, executable code is not provided on the distribution media. Compiling the source code requires the Microsoft C v5.1 compiler, Microsoft QuickC v2.0, the Microsoft Mouse Library, EPIX Image Processing Libraries, the Microway NDP-Fortran-386 v2.1 compiler, and the Media Cybernetics HALO Professional Graphics Kernal System. Due to the complexities of the machine requirements, COSMIC strongly recommends the purchase and review of the documentation prior to the purchase of the program. The source code, and sample input and output files are provided in PKZIP format; the PKUNZIP utility is included. PDT was developed in 1990. All trade names used are the property of their respective corporate owners.

Wernet, M. P.

1994-01-01

369

Microvascular relations of the trigeminal nerve: an anatomical study.  

PubMed

The neurovascular relationships in the trigeminal root entry zone were studied in 130 trigeminal root entry zones of 65 cadavers. No history of facial or trigeminal pain had been obtained during life in these subjects. The technique of intravascular injection, which allowed good visualization and evaluation of the neurovascular relationships, is described. A total of 42 examples of contact with the root entry zone and 10 examples of compression were identified. In 30 of the examples of contact, the finding could be related to an artery; in the other examples, it appeared to be due to veins. Of the arterial compressions, the superior cerebellar artery was responsible in 53.8%, the anterior inferior cerebellar artery was responsible in 25.6%, and pontine branches of the basilar artery were responsible for the remaining 20.6%. Only one instance of unequivocal compression by a vein was found. Other anatomical observations of interest are reported. The absence of a history of trigeminal neuralgia in the 7% of examined nerves in which root entry zone showed arterial compression is in marked contrast to the finding of 80% or more in the operative series for trigeminal neuralgia. It seems that vascular compressions may be the predominant but not the sole cause of trigeminal neuralgia. PMID:3785594

Klun, B; Prestor, B

1986-10-01

370

Intermuscular lipoma of the gluteus muscles compressing the sciatic nerve: an inverted sciatic hernia.  

PubMed

The authors report the case of a 50-year-old woman with a benign intermuscular lipoma of the gluteus compressing the sciatic nerve in its course through the sciatic notch. This benign soft-tissue tumor extended into the pelvis, displacing the rectum laterally. Resection was necessary to alleviate symptoms and prevent irreversible damage of the nerve. Wide exposure of the piriformis muscle and sciatic nerve via a transgluteal approach allowed safe lesion removal, and thus avoiding a laparotomy to resect the intrapelvic extension of the tumor. This report features a curious case of soft-tissue tumor growth across the sciatic foramen forming an inverted sciatic hernia. The authors' proposed approach was simple and safe and avoided a laparotomy. PMID:22900844

López-Tomassetti Fernández, Eudaldo M; Hernández, Juan Ramón Hernández; Esparragon, Jose Ceballos; García, Angel Turegano; Jorge, Valentin Nuñez

2012-10-01

371

Axoplasm Isolation from Peripheral Nerve  

PubMed Central

Localized changes in the composition of axonal cytoplasm (axoplasm) are critical for many biological processes, including axon guidance, responses to injury, neurite outgrowth, and axon-glia interactions. Biochemical and molecular studies of these mechanisms have been heavily focused on in vitro systems, due to the difficulty of obtaining subcellular extracts from mammalian tissues in vivo. Since in vitro systems might not replicate the in vivo situation, reliable methods of axoplasm extraction from whole nerve would be helpful for mechanistic studies on axons. Here we develop and evaluate a new procedure for preparation of axoplasm from rat peripheral nerve, based on incubation of separated short segements of nerve fascicles in hypotonic medium to separate myelin and lyse non-axonal structures, followed by extraction of the remaining axon-enriched material. We show that this new procedure reduces serum and glial cell contamination, and facilitates proteomic analyses of axonal contents.

Rishal, Ida; Michaelevski, Izhak; Rozenbaum, Meir; Shinder, Vera; Medzihradszky, Katalin F.; Burlingame, Alma L.; Fainzilber, Mike

2010-01-01

372

Management of optic nerve gliomas.  

PubMed Central

Seventeen patients thought to have orbital optic nerve gliomas when first seen have been reviewed after up to 12 years. Enlargement of the optic canal was present in 15 of the 16 patients examined, but this finding was unreliable as an indicator of the posterior extent of the tumour. Nine patients had a stable course with little change over a period of up to 8 years; there was optic atrophy in all and neurofibromatosis was relatively common (7/9). Eight patients showed progressive enlargement of the tumour; 6 had swollen discs, and the incidence of neurofibromatosis was relatively low (3/8). The optic nerve was excised in 7 of the latter group. Biopsies of the optic nerve taken from the region of maximal enlargement were difficult to interpret and unhelpful in planning management. Radical surgery should be reserved for the minority of patients in whom there is progressively enlarging tumour without evidence of chiasmal involvement. Images

Wright, J. E.; McDonald, W. I.; Call, N. B.

1980-01-01

373

Bucky gel actuator displacement: experiment and model  

NASA Astrophysics Data System (ADS)

Bucky gel actuator (BGA) is a dry electroactive nanocomposite which is driven with a few volts. BGA’s remarkable features make this tri-layered actuator a potential candidate for morphing applications. However, most of these applications would require a better understanding of the effective parameters that influence the BGA displacement. In this study, various sets of experiments were designed to investigate the effect of several parameters on the maximum lateral displacement of BGA. Two input parameters, voltage and frequency, and three material/design parameters, carbon nanotube type, thickness, and weight fraction of constituents were selected. A new thickness ratio term was also introduced to study the role of individual layers on BGA displacement. A model was established to predict BGA maximum displacement based on the effect of these parameters. This model showed good agreement with reported results from the literature. In addition, an important factor in the design of BGA-based devices, lifetime, was investigated.

Ghamsari, A. K.; Jin, Y.; Zegeye, E.; Woldesenbet, E.

2013-02-01

374

Nonlinear stability analysis of miscible displacements  

Microsoft Academic Search

A simulator for three-dimensional horizontal miscible displacements in porous media is developed. Using this simulator, we examine the initiation and development of instabilities, viscous fingers and gravity tongues.

Shih-Hsien Chang; John C. Slattery

1990-01-01

375

Hydrocarbon Displacement by Carbon Dioxide Dispersions.  

National Technical Information Service (NTIS)

The US Department of Energy's (DOE) Morgantown Energy Technology Center (METC) is investigating methods to control the mobility of carbon dioxide for use in gas miscible displacements of hydrocarbons that are found in petroleum reservoirs. Carbon dioxide ...

J. R. Duda

1986-01-01

376

Computer Simulation of High Energy Displacement Cascades.  

National Technical Information Service (NTIS)

A methodology developed for modeling many aspects of high energy displacement cascades with molecular level computer simulations is reviewed. The initial damage state is modeled in the binary collision approximation (using the MARLOWE computer code), and ...

H. L. Heinisch

1988-01-01

377

Surgical extraction of impacted inferior third molars at risk for inferior alveolar nerve injury.  

PubMed

The objective of the study was to prospectively assess the intraoperative findings and the radiographic signs of a study population of patients with impacted third molars at risk of inferior alveolar nerve injury. One hundred thirty-four patients with impacted mandibular third molars at risk for nerve injury were included in the study. Radiographic signs of possible close relationship between the 2 structures and intraoperative exposition or damage of the inferior alveolar nerve were recorded. The follow-up controls comprised clinical examinations and assessment for the sensation of the lower lip and chin. In 24 patients, a real contiguity was encountered between the third molars and nerve. Among these, intraoperative neural exposition was observed in 19 patients. Four patients complained of postoperative temporary hypoesthesia. No deficit of sensibility was found in cases with no exposition of the nerve. The accidental exposition of the inferior alveolar nerve is associated with an increased risk for neural injuries. At panoramic radiograph, the presence of signs of bifid and radiolucent apex, superimposition, and radiolucent root band should be considered at high risk for neural damage. PMID:21119486

Gallesio, Cesare; Berrone, Mattia; Ruga, Emanuele; Boffano, Paolo

2010-11-01

378

Autoradiographic location of sensory nerve endings in dentin of monkey teeth  

SciTech Connect

We have used the autoradiographic method to locate trigeminal nerve endings in monkey teeth. The nerve endings were labeled in two adult female Macaca fascicularis by 20 hours of axonal transport of radioactive protein (/sup 3/H-L-proline). We found a few labeled axons in contralateral mandibular central incisors and one mandibular canine. In ipsilateral teeth, numerous myelinated and unmyelinated axons were labeled; they formed a few terminal branches in the roots but primarily branched in the crown to form the peripheral plexus of Raschkow and to terminate as free endings in the odontoblast layer, predentin, and as far as 120 micrometers into dentinal tubules. Electron microscopic autoradiography showed that the radioactive axonally transported protein was confined to sensory axons and endings; odontoblasts and dentin matrix were not significantly labeled. Labeled free nerve endings were closely apposed to odontoblasts in dentin but did not form distinctive junctions with them. Nerve endings were most numerous in the regular tubular dentin of the crown adjacent to the tip of the pulp horn, occurring in at least half of the dentinal tubules there. Our results show tha dentinal sensory nerve endings in primate teeth can be profuse, sparse, or absent depending on the location and structure of dentin and its adjacent pulp. When dentin was innervated, the tubules were straight and contained odontoblast processes, the predentin was wide, the odontoblast cell bodies were relatively columnar, and there was an adjacent cell-free zone and pulpal nerve plexus.

Byers, M.R.; Dong, W.K.

1983-04-01

379

Atmospheric pressure loading displacement of SLR stations  

Microsoft Academic Search

This paper addresses the local displacement at ground stations of the world-wide Satellite Laser Ranging (SLR) network induced by atmospheric pressure variations. Since currently available modelling options do not satisfy the requirements for the target application (real-time availability, complete coverage of SLR network), a new representation is developed. In a first step, the 3-dimensional displacements are computed from a 6-hourly

D. Bock; R. Noomen; H.-G. Scherneck

2005-01-01

380

Nerve supply to the pelvis (image)  

MedlinePLUS

The nerves that branch off the central nervous system (CNS) provide messages to the muscles and organs for normal ... be compromised. In multiple sclerosis, the demyelinization of nerve cells may lead to bowel incontinence, bladder problems ...

381

Specialized Nerve Tests: EMG, NCV and SSEP  

MedlinePLUS

... muscle cells when they are activated by the nerves connected to them. Specialists analyze these signals to detect medical abnormalities in the spinal cord, nerves and the muscles that are connected to specific ...

382

Infraspinatus muscle atrophy from suprascapular nerve compression.  

PubMed

Muscle weakness without pain may signal a nerve compression injury. Because these injuries should be identified and treated early to prevent permanent muscle weakness and atrophy, providers should consider suprascapular nerve compression in patients with shoulder muscle weakness. PMID:24463748

Cordova, Christopher B; Owens, Brett D

2014-02-01

383

CDC's CHEMPACK Project: Nerve Agent Antidote Storage.  

National Technical Information Service (NTIS)

Nerve agent antidotes in the CHEMPACK project were stored at temperatures required by the Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC) implemented procedures to ensure the quality of nerve agent antidotes in the...

2009-01-01

384

Management of Spasticity with Phenol Nerve Block.  

National Technical Information Service (NTIS)

Contents: Spasticity as a social problem; Complications and side effects of spasticity; History of peripheral phenol nerve block; Management of clinical pictures by selective phenol block; Physiological studies; Abnormal innervation and phenol nerve block...

A. A. Khalili H. B. Betts

1970-01-01

385

Cranial nerve paralysis following carotid endarterectomy.  

PubMed

During the past seven years 347 patients have been entered into a data bank at the Duke University Medical Center for evaluation of transient neurologic ischemia. One hundred fifty eight of these patients had carotid endarterectomies of whom 24 (15.1%) developed 26 (16.4%) peripheral cranial nerve palsies. Injury to the peripheral portion of the hypoglossal nerve was noted in 13 patients, to the cervical branch of the facial nerve in five and to the recurrent laryngeal nerve branch of the vagus in eight. Complete recovery of nerve function usually occurred within four months but residual deficit was present at one year in two patients with facial nerve and four with hypoglossal nerve involvement. Even though these complications of carotid endarterectomy are generally benign and transient, the frequency of occurrence can be reduced if careful attention is given to anatomic localization of the cranial nerves during surgery. PMID:6695421

Massey, E W; Heyman, A; Utley, C; Haynes, C; Fuchs, J

1984-01-01

386

Frequency response of polypyrrole trilayer actuator displacement  

NASA Astrophysics Data System (ADS)

Conducting polymer trilayers are attractive for use in functional devices, given low actuation voltages, operation in air and potentially useful stresses and strains; however, their dynamic behavior must be understood from an engineering perspective before they can be effectively incorporated into a design. As a step towards the identification of the actuator dynamics, frequency response analysis has been performed to identify the magnitude and phase shift of displacement in response to a sinusoidal voltage input. The low damping of the trilayer operating in air and the use of a laser displacement sensor has allowed the frequency response to be continuously identified up to 100Hz, demonstrating a resonant peak at 80Hz for a 10mm long actuator. Two linear transfer function models have been fitted to the frequency response of the trilayer displacement (i) a 3rd order model to represent the dynamics below 20Hz and (ii) a higher complexity 6th order model to also include the resonant peak. In response to a random input signal, the 3rd order model coarsely follows the experimental identified displacement, while the 6th order model is able to fully simulate the real trilayer movement. Step responses have also been obtained for the 3rd and 6th order transfer functions, with both models capable of following the first 4 seconds of experimental displacement. The application of empirical transfer function models will facilitate accurate simulation and analysis of trilayer displacement, and will lead to the design of accurate positional control systems.

John, Stephen; Alici, Gursel; Cook, Christopher

2008-05-01

387

Displacement chromatography applied to trace component analysis  

SciTech Connect

Displacement chromatography has been used primarily for the isolation of relatively large quantities of materials in preparative scale separations. The authors show that it also offers advantages for the enrichment of trace components. During displacement development, significant compression of the trace component bands occurs. This enrichment is studied both experimentally and theoretically. The theoretical model is based on the solution of the mass balance equations for nonlinear chromatography, assuming competitive Langmuir isotherms. The system studied experimentally consisted of parts-per-million levels of {beta}-naphthylamine and an impurity of the naphthylamine as the sample and diethyl phthalate as the displacer. The band profiles of the trace components were monitored by fluorescence detection while the displacer was monitored by UV absorbance. Wavelengths were chosen such that the profiles of the sample and the displacer could be monitored independently. Trace enrichment by band compression was achieved by increasing the displacer concentration. Experimental results show very narrow bands at enhanced concentrations as compared to the relatively broad Gaussian-shaped profiles observed in linear elution chromatography. The experimental results are in agreement with theoretical predictions of peak shape.

Ramsey, R.; Katti, A.M.; Guiochon, G. (Univ. of Tennessee, Knoxville (USA) Oak Ridge National Laboratory, TN (USA))

1990-12-01

388

Root hydrotropism: an update.  

PubMed

While water shortage remains the single-most important factor influencing world agriculture, there are very few studies on how plants grow in response to water potential, i.e., hydrotropism. Terrestrial plant roots dwell in the soil, and their ability to grow and explore underground requires many sensors for stimuli such as gravity, humidity gradients, light, mechanical stimulations, temperature, and oxygen. To date, extremely limited information is available on the components of such sensors; however, all of these stimuli are sensed in the root cap. Directional growth of roots is controlled by gravity, which is fixed in direction and intensity. However, other environmental factors, such as water potential gradients, which fluctuate in time, space, direction, and intensity, can act as a signal for modifying the direction of root growth accordingly. Hydrotropism may help roots to obtain water from the soil and at the same time may participate in the establishment of the root system. Current genetic analysis of hydrotropism in Arabidopsis has offered new players, mainly AHR1, NHR1, MIZ1, and MIZ2, which seem to modulate how root caps sense and choose to respond hydrotropically as opposed to other tropic responses. Here we review the mechanism(s) by which these genes and the plant hormones abscisic acid and cytokinins coordinate hydrotropism to counteract the tropic responses to gravitational field, light or touch stimuli. The biological consequence of hydrotropism is also discussed in relation to water stress avoidance. PMID:23258371

Cassab, Gladys I; Eapen, Delfeena; Campos, María Eugenia

2013-01-01

389

Continuous Vagal Nerve Stimulation for Recurrent Laryngeal Nerve Protection in Thyroid Surgery  

Microsoft Academic Search

Introduction: Newly developed vagal stimulation probes permit continuous intraoperative neuromonitoring of the recurrent laryngeal nerve during thyroid resection. Complete signal loss indicates damage of the nerve. There is no other criterion so far to warn before imminent nerve function impairment. Methods: In 100 patients, thyroid resection (188 nerves at risk, 52 thyroidectomies, 21 Dunhill resections, 12 hemithyroidectomies, 5 two-sided subtotal

J. Jonas

2010-01-01

390

Surgical Approaches to Facial Nerve Deficits  

PubMed Central

The facial nerve is one of the most commonly injured cranial nerves. Once injured, the effects on form, function, and psyche are profound. We review the anatomy of the facial nerve from the brain stem to its terminal branches. We also discuss the physical exam findings of facial nerve injury at various levels. Finally, we describe various reconstructive options for reanimating the face and restoring both form and function.

Birgfeld, Craig; Neligan, Peter

2011-01-01

391

Proximal Sciatic Nerve Intraneural Ganglion Cyst  

PubMed Central

Intraneural ganglion cysts are nonneoplastic, mucinous cysts within the epineurium of peripheral nerves which usually involve the peroneal nerve at the knee. A 37-year-old female presented with progressive left buttock and posterior thigh pain. Magnetic resonance imaging revealed a sciatic nerve mass at the sacral notch which was subsequently revealed to be an intraneural ganglion cyst. An intraneural ganglion cyst confined to the proximal sciatic nerve has only been reported once prior to 2009.

Swartz, Karin R.; Wilson, Dianne; Boland, Michael; Fee, Dominic B.

2009-01-01

392

Cranial nerve injuring during carotid endarterectomy.  

PubMed Central

Injury to the greater auricular, hypoglossal and superior laryngeal nerves during carotid endarterectomy is preventable. A knowledge of regional anatomy and the mechanisms of such injury allows prevention of this complication. Unilateral individual nerve injury is generally well tolerated, but bilateral or combined nerve injuries can pose a serious threat to life. Minor modifications in technique aid greatly in avoiding nerve injury. Images Fig. 1.

Verta, M J; Applebaum, E L; McClusky, D A; Yao, J S; Bergan, J J

1977-01-01

393

40 CFR 86.419-78 - Engine displacement, motorcycle classes.  

Code of Federal Regulations, 2010 CFR

...displacement, motorcycle classes. (a)(1) Engine displacement shall be calculated using nominal engine values and rounded to the nearest whole...accordance with ASTM E 29-67. (2) For rotary engines, displacement means the maximum...

2009-07-01

394

40 CFR 86.419-2006 - Engine displacement, motorcycle classes.  

Code of Federal Regulations, 2010 CFR

...displacement, motorcycle classes. (a)(1) Engine displacement shall be calculated using nominal engine values and rounded to the nearest whole...reference in § 86.1). (2) For rotary engines, displacement means the maximum...

2009-07-01

395

40 CFR 86.419-78 - Engine displacement, motorcycle classes.  

Code of Federal Regulations, 2010 CFR

...displacement, motorcycle classes. (a)(1) Engine displacement shall be calculated using nominal engine values and rounded to the nearest whole...accordance with ASTM E 29-67. (2) For rotary engines, displacement means the maximum...

2010-07-01

396

40 CFR 86.419-2006 - Engine displacement, motorcycle classes.  

Code of Federal Regulations, 2010 CFR

...displacement, motorcycle classes. (a)(1) Engine displacement shall be calculated using nominal engine values and rounded to the nearest whole...reference in § 86.1). (2) For rotary engines, displacement means the maximum...

2010-07-01

397

Peptidergic (VIP) nerves in the pancreas  

Microsoft Academic Search

Vasoactive intestinal peptide (VIP) was found to occur in nerves in the pancreas of all species examined, as demonstrated by immunohistochemistry. Immunoreactive nerve terminals were seen to run in the stroma, around acini, and in the wall of blood vessels. Clusters of immunoreactive nerve cell bodies were encountered in the parenchyma; in addition other ganglia were densely innervated by VIP

F. Sundler; J. Alumets; R. Håkanson; J. Fahrenkrug; O. Schaffalitzky de Muckadell

1978-01-01

398

Cranial Nerves Model - PowerPoint Presentation  

NSDL National Science Digital Library

Lesson is designed to introduce students to cranial nerves through the use of an introductory lecture. Students will then create a three-dimensional model of the cranial nerves. An information sheet will accompany the model in order to help students learn crucial aspects of the cranial nerves.

Juliann Garza (University of Texas-Pan American Physician Assistant Studies)

2010-08-16

399

Trigeminal nerve: Anatomic correlation with MR imaging  

SciTech Connect

Through correlation with cryomicrotic sections, the appearance of the trigeminal nerve and its branches on magnetic resonance images is described in healthy individuals and in patients with tumors involving this nerve. Coronal images are best for defining the different parts of the nerve and for making a side-to-side comparison. Sagittal images are useful to demonstrate tumors involving the Gasserian ganglion.

Daniels, D.L.; Pech, P.; Pojunas, K.W.; Kilgore, D.P.; Williams, A.L.; Haughton, V.M.

1986-06-01

400

21 CFR 882.5275 - Nerve cuff.  

Code of Federal Regulations, 2010 CFR

...8 2010-04-01 2010-04-01 false Nerve cuff. 882.5275 Section 882.5275 Food...Neurological Therapeutic Devices § 882.5275 Nerve cuff. (a) Identification. A nerve cuff is a tubular silicone rubber sheath...

2010-04-01

401

21 CFR 882.5275 - Nerve cuff.  

Code of Federal Regulations, 2010 CFR

...8 2009-04-01 2009-04-01 false Nerve cuff. 882.5275 Section 882.5275 Food...Neurological Therapeutic Devices § 882.5275 Nerve cuff. (a) Identification. A nerve cuff is a tubular silicone rubber sheath...

2009-04-01

402

Neurotransmitter synthesis in Limulus ventral nerve photoreceptors  

Microsoft Academic Search

Summary Radiochemical precursor compounds for neurotransmitters were incubated withLimulus ventral nerve photoreceptor preparations. Octopamine was preferentially synthesized by a photoreceptor rich fraction of the nerve, acetylcholine was made by a photoreceptor poor fraction, and ?-aminobutyric acid was made about equally well in both fractions. The possibility that the ventral nerve photoreceptor cells serve a neurosecretory function in the adultLimulus is

B. A. Battelle; E. A. Kravitz; H. Stieve

1979-01-01

403

Refractory Period in Human Sensory Nerve Fibres  

Microsoft Academic Search

Relative and absolute refractory periods were determined in sensory fibres of 24 median nerves and in 19 sural nerves of 30 volunteers aged 20–60 years, who had no sign of a neuromuscular disorder. The critical interval of conduction (absolute refractory period) was found to be about 0.7 msec. In median as well as in sural nerve the relative refractory periods

W. Tackmann; H. J. Lehmann

1974-01-01

404

Silicone oil–associated optic nerve degeneration  

Microsoft Academic Search

PURPOSE: To report the frequency and extent of silicone oil migration into the optic nerve during silicone oil endotamponade.METHODS: Histopathologic analysis of 74 eyes enucleated after silicone oil endotamponade.RESULTS: In 14 of 74 enucleated eyes (24%), optically empty vacuoles regarded as silicone oil vacuoles were observed in the retrolaminar optic nerve. In three eyes, silicone oil in the optic nerve

Maike Budde; Claus Cursiefen; Leonard M Holbach; Gottfried O. H Naumann

2001-01-01

405

Spatial characterization of root reinforcement at stand scale: Theory and case study  

NASA Astrophysics Data System (ADS)

We propose a new upscaling approach for quantify root reinforcement at the stand scale using the spatially explicit root bundle model (RBM) for describing pullout force-displacement behavior coupled with a model for lateral root distribution. The root distribution model was calibrated using data of two excavated soil profiles, and validated with measurements of root distribution along the scarp of an artificially rainfall-triggered landslide in a vegetated hillslope above the Rhine river in northern Switzerland. Results show that the model overestimates small root density (1-3 mm diameter), leading to an error in estimated maximum root reinforcement of about 28%. For comparison, the most commonly used model of Wu overpredicts root reinforcement by a factor of 3. The spatial variability of estimated maximum root reinforcement within the forest stand is high, ranging from 0 to 20 kPa. Most soil reinforcement by roots occurs close to the tree stem or in zones where root systems overlap. The new approach provides a detailed description of maximum root reinforcement on a slope, an essential element for the prediction of shallow landslides and the management of protection forests.

Schwarz, M.; Cohen, D.; Or, D.

2012-10-01

406

Lithium Enhances Axonal Regeneration in Peripheral Nerve by Inhibiting Glycogen Synthase Kinase 3? Activation  

PubMed Central

Brachial plexus injury often involves traumatic root avulsion resulting in permanent paralysis of the innervated muscles. The lack of sufficient regeneration from spinal motoneurons to the peripheral nerve (PN) is considered to be one of the major causes of the unsatisfactory outcome of various surgical interventions for repair of the devastating injury. The present study was undertaken to investigate potential inhibitory signals which influence axonal regeneration after root avulsion injury. The results of the study showed that root avulsion triggered GSK-3? activation in the injured motoneurons and remaining axons in the ventral funiculus. Systemic application of a clinical dose of lithium suppressed activated GSK-3? in the lesioned spinal cord to the normal level and induced extensive axonal regeneration into replanted ventral roots. Our study suggests that GSK-3? activity is involved in negative regulation for axonal elongation and regeneration and lithium, the specific GSK-3? inhibitor, enhances motoneuron regeneration from CNS to PNS.

Su, Huanxing; Yuan, Qiuju; Qin, Dajiang; Yang, Xiaoying; So, Kwok-Fai; Wu, Wutian

2014-01-01

407

Identifying motor and sensory myelinated axons in rabbit peripheral nerves by histochemical staining for carbonic anhydrase and cholinesterase activities  

NASA Technical Reports Server (NTRS)

Carbonic anhydrase (CA) and cholinesterase (CE) histochemical staining of rabbit spinal nerve roots and dorsal root ganglia demonstrated that among the reactive myeliated axons, with minor exceptions, sensory axons were CA positive and CE negative whereas motor axons were CA negative and CE positive. The high specificity was achieved by adjusting reaction conditions to stain subpopulations of myelinated axons selectively while leaving 50 percent or so unstained. Fixation with glutaraldehyde appeared necessary for achieving selectivity. Following sciatic nerve transection, the reciprocal staining pattern persisted in damaged axons and their regenerating processes which formed neuromas within the proximal nerve stump. Within the neuromas, CA-stained sensory processes were elaborated earlier and in greater numbers than CE-stained regenerating motor processes. The present results indicate that histochemical axon typing can be exploited to reveal heterogeneous responses of motor and sensory axons to injury.

Riley, Danny A.; Sanger, James R.; Matloub, Hani S.; Yousif, N. John; Bain, James L. W.

1988-01-01

408

Primary optic nerve sheath meningioma  

Microsoft Academic Search

Fifty patients with optic nerve sheath meningiomas have been reviewed with a follow-up of up to 15 years. The median age at onset of their symptoms was 40.0 years. The majority were middle aged females with a slowly progressive lesion. More aggressive lesions were encountered in a younger, predominantly male group of patients with frequent intracranial involvement. Our experience indicates

J E Wright; A A McNab; W I McDonald

1989-01-01

409

Allotransplanted Neurons Used to Repair Peripheral Nerve Injury Do Not Elicit Overt Immunogenicity  

PubMed Central

A major problem hindering the development of autograft alternatives for repairing peripheral nerve injuries is immunogenicity. We have previously shown successful regeneration in transected rat sciatic nerves using conduits filled with allogeneic dorsal root ganglion (DRG) cells without any immunosuppression. In this study, we re-examined the immunogenicity of our DRG neuron implanted conduits as a potential strategy to overcome transplant rejection. A biodegradable NeuraGen® tube was infused with pure DRG neurons or Schwann cells cultured from a rat strain differing from the host rats and used to repair 8 mm gaps in the sciatic nerve. We observed enhanced regeneration with allogeneic cells compared to empty conduits 16 weeks post-surgery, but morphological analyses suggest recovery comparable to the healthy nerves was not achieved. The degree of regeneration was indistinguishable between DRG and Schwann cell allografts although immunogenicity assessments revealed substantially increased presence of Interferon gamma (IFN-?) in Schwann cell allografts compared to the DRG allografts by two weeks post-surgery. Macrophage infiltration of the regenerated nerve graft in the DRG group 16 weeks post-surgery was below the level of the empty conduit (0.56 fold change from NG; p<0.05) while the Schwann cell group revealed significantly higher counts (1.29 fold change from NG; p<0.001). Major histocompatibility complex I (MHC I) molecules were present in significantly increased levels in the DRG and Schwann cell allograft groups compared to the hollow NG conduit and the Sham healthy nerve. Our results confirmed previous studies that have reported Schwann cells as being immunogenic, likely due to MHC I expression. Nerve gap injuries are difficult to repair; our data suggest that DRG neurons are superior medium to implant inside conduit tubes due to reduced immunogenicity and represent a potential treatment strategy that could be preferable to the current gold standard of autologous nerve transplant.

Liu, Weimin; Ren, Yi; Bossert, Adam; Wang, Xiaowei; Dayawansa, Samantha; Tong, Jing; He, Xiaoshen; Smith, Douglas H.; Gelbard, Harris A.; Huang, Jason H.

2012-01-01

410

Release of axonally transported material from an in vitro amphibian sciatic nerve preparation  

SciTech Connect

The rapid axonal transport of a pulse of (35S)methionine-labelled material was used to study the release of transported material from amphibian nerve maintained in vitro. Following creation of a moving pulse of activity in a dorsal root ganglion-sciatic nerve preparation, the ganglion was removed and the nerve placed in a three-compartment tray, the section of nerve in the middle compartment containing no truncated branches (unbranched section). All three compartments were filled with a saline solution that in some studies contained nonradioactive methionine (1.0 mmol/L). Analysis of studies in which nonradioactive methionine was absent revealed that labelled material appeared in the bathing solution of the end compartments that contained truncated branches, but not in the solution of the middle (unbranched) compartment. The quantity of label released in the branched compartments was approximately 6% of that remaining in the corresponding section of nerve following an 18-20 h incubation period. However, when nonradioactive methionine was present, all compartments showed an additional activity in the bathing solution of approximately 10% of that remaining in the nerve. In another study in which a position-sensitive detector of ionizing radiation was used to monitor progress of the pulse, it was found that activity did not enter the bathing solution of a compartment prior to the pulse of activity. It is concluded that in the absence of methionine from the bathing solution, axonally transported material is released only from regions of nerve that contain severed axons; however, the presence of methionine allows transported material to be released from nerve containing intact axons. Ultrafiltration studies and thin-layer chromatography revealed the majority of material released to be of low-molecular weight (less than 30,000 daltons) and not free (35S)methionine.

Snyder, R.E.

1988-04-01

411

Autonomous dynamic displacement estimation from data fusion of acceleration and intermittent displacement measurements  

NASA Astrophysics Data System (ADS)

Addressing the importance of displacement measurement of structural responses in the field of structural health monitoring, this paper presents an autonomous algorithm for dynamic displacement estimation from acceleration integration fused with displacement data intermittently measured. The presented acceleration integration algorithm of multi-rate Kalman filtering distinguishes itself from the past study in the literature by explicitly considering acceleration measurement bias. Furthermore, the algorithm is formulated by unique state definition of integration errors and error dynamics system modeling. To showcase performance of the algorithm, a series of laboratory dynamic experiments for measuring structural responses of acceleration and displacement are conducted. Improved results are demonstrated through comparison between the proposed and past study.

Kim, Junhee; Kim, Kiyoung; Sohn, Hoon

2014-01-01

412

Corn root gravitropism  

NSDL National Science Digital Library

Gravitropism is the turning or growing in a different direction of a plant in response to gravity. This corn plant's root grows downward and exhibits positive gravitropism because it is growing toward gravity's pull.

Roger P. Hangarter (Indiana University;Department of Biology)

2000-01-01

413

Nerve conduction studies in adrenomyeloneuropathy.  

PubMed Central

OBJECTIVE--Adrenomyeloneuropathy (AMN) is an X linked metabolic disorder presenting with progressive spastic paraparesis in the third to fifth decade of life. Although peripheral neuropathy is also present in most patients, prominent pyramidal signs may make its clinical recognition difficult. The objective was to characterise the peripheral neuropathy in patients with AMN by nerve conduction studies. METHODS--Nerve conduction studies were performed in 99 men known to have AMN and in 38 heterozygous women, all of whom had neurological disabilities. RESULTS--Of the 13 variables obtained, at least one was abnormal in 82% of patients. The abnormalities were more common in men than in women (87% v 67%); in legs than in arms (77% v 38%); in motor than in sensory conduction (80% v 39%); and in latency (distal and F wave) and velocity compared with amplitude (80% v 29%). Twenty six patients had at least one nerve variable value in the demyelinating range. Four variables (sural velocity, peroneal amplitude, peroneal velocity, and peroneal F wave) were correlated with the expanded disability status scale; five variables (peroneal velocity, tibial H reflex, median distal latency, median conduction velocity, and median F wave latency) were correlated with serum very long chain fatty acids (VLCFAs); and two variables (sural amplitude and peroneal distal latency) were more likely to be abnormal in patients with normal adrenal function than in patients with Addison's disease. CONCLUSIONS--Nerve conduction studies in patients with AMN are often abnormal and suggest a mixture of axonal loss and multifocal demyelination. Their correlation with disability status and serum VLCFAs suggests that measures from nerve conduction studies may be useful in evaluating future treatments. Images

Chaudhry, V; Moser, H W; Cornblath, D R

1996-01-01